DOCSLIB.ORG

The Metallurgy of Some Carat Gold Jewellery Alloys

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Metallurgy of Some Carat Gold Jewellery Alloys View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Springer - Publisher Connector The Metallurgy of Some Carat Gold Jewellery Alloys PART II — NICKEL CONTAINING WHITE GOLD ALLOYS Allen S. McDonald and George H. Sistare Handy & Harman, Fairfield, Connecticut, U.S.A. The first part of this article detailed the relationships existing between the composition, metallurgical structure and properties of coloured jewellery gold alloys. In this second part, the same treatment is applied to nickel containing white gold alloys. Most commercial white gold alloys used in North Cu wt.o'o Cu' = x 100 (per cent) America are based on the gold-copper-nickel or the Cu wt.% + Ni wt.% gold-copper-nickel-zinc system. In other parts of the world, alloys in which palladium is substituted for all As in the case of coloured gold alloys where the or part of the nickel are also used. The latter will, alloys were discussed in terras of three parameters: however, not be discussed in this article. caratage, Ag', and zinc content, gold-copper-nickel- zinc white gold alloys will be discussed in terms of The Metallurgical System three parameters: caratage, Cu' and zinc content. If the gold-copper-nickel system is approached as was the gold-silver-copper system by considering the Useful Jewellery Alloys three binary phase diagrams gold-nickel, nickel- The area of the ternary system occupied by useful copper, and copper-gold in Figure 8, the solid state white jewellery gold alloys is far more restricted than immiscibility field in the nickel-gold system would be in the case of coloured gold alloys. Historically, the expected to intrude into the ternary field and, in- present nickel-bearing white gold alloys were derived deed it does, as shown in Figure 9. If Figure 9 is com- from alloys introduced in the 1920's as substitutes for pared with Figure 3 in Part I, it will be seen that the platinum for diamond settings. A typical early alloy systems are similar but are differently orien- consisted of 81 gold/16 nickel/3 zinc weight per cent. tated with respect to gold. In the gold-silver-copper If this 19 1/2 carat alloy is converted to lower caratage, system, the two-phase field extends from the side op- the workability deteriorates rapidly. At 18 carat, some posite the gold corner, whereas in the gold-copper- copper is essential for practical workability and nickel system, the two-phase field extends from the sizeable amounts are needed at 14 and 10 carat. side opposite the copper corner. Thus, each constant However, there is a limit to the amount of copper that carat level in the gold-silver-copper alloy system falls can be tolerated while retaining a white colour. Zinc, on a line which cuts symmetrically through the im- which is an ingredient of most nickel-bearing white miscibility field. From a metallurgical point of view, gold alloys, tends to enhance the whitening effect of it would be logical to study the gold-copper-nickel nickel and to compensate somewhat for the colouring system by considering alloys along lines which cut effect of copper. However, zinc also tends to increase symmetrically through the immiscibility field in firecracking. That is, when nickel-bearing white gold Figure 9. Unfortunately, such lines are lines of cons- alloys are lightly worked (less than the equivalent of tant copper content and the alloys along them bear no about 50 per cent reduction in cross section) prior to relation to jewellery alloys. Therefore, the less logical annealing, cracking may occur at the grain boundaries but more pertinent choice of alloys on lines of cons- on annealing. This fact is well known to the industry. tant gold content has to be made, although such lines The metallurgical reason for the phenomenon has cut asymmetrically through the immiscibility field. still to be precisely defined. On this basis, schematic quasi-binary sections at 18, The compositions of white gold alloys that have 14, and 10 carat are shown in Figure 10 with, on the evolved over the years are the result of an empirical abscissa, a plot of the parameter Cu' defined as: compromise between these various factors. In Figure 128 Fig. 8 Gold-nickel, nickel-topper and copper-gold GOLD-NICKEL binary phase diagrams. Some comments on the copper- o C NICKEL ATOMIC PER CENT gold diagrams were made in the caption for Figure 1. 10203040 50 60 70 80 90 95 1600 The existence of a large solid-state immiscibility field in the gold-nickel system has an important influence on 1455° the metallurgical properties of ternary gold-copper- 1400 i • nickel alloys. After (1) LIQUID 1200 1064 ° 1000 SOLID SOLUTION COPPER -GOLD -17 "(Au,Ni) 800 - GOLD ATOMIC PER CENT 821 ° 54.4/o °c 10 20 30 40 50 60 70 8090 1100 600 «(Au IMMISCIBILITY a l) "(Au)'"(Ni) 1050 400 Au 10 20 30 40 50 60 70 80 90 Ni NICKEL WEIGHT PER CENT 1000 NICKEL-COPPER 950 COPPER ATOMIC PER CENT oC i^u,w ,0 70 30 40 50 60 70 80 90 900 ^f t— 911°801°I° tj 1500 1455 ° 450 1400 LIQUID 410 °,756 400 390°,50.8°/ 1300 350 1200 SOLID SOLUTION AuCu3 j AuCu "(Cu,Ni) 300 1100 1084 285 1 358° 1 322 ° CURIE TEMPERATURE 250 300 ................ .......... 24Ó ) I\ IMMISCIBILITY a (Cu a Ni "(Cu) 200 00 Cu 10 20 30 40 50 60 7^ 0 80 90 Au Ni 10 20 30 40 50 60 70 80 90 Cu GOLD WEIGHT PER CENT COPPER WEIGHT PER CENT 11, the areas wherein almost all white jewellery alloys Au have been made are covered by the bold blocks on the carat lines. The broken lines on the diagram indicate the approximate boundary at which white alloys tend 60 to become yellowish. The gold-nickel binary diagram on the left is included to help the reader visualise the intrusion of the immiscibility field into the ternary 50 diagram. Y Discussing the coloured gold alloys, in terms of 40'0 `types' depending on carat, Ag', and zint content was 70 /'T90 30 found convenient. White alloys cannot be ordered as nicely. However, it will facilitate the discussion if the 90 80 \ yuv "cLUTIO,Ni) 20 10 alloys are arranged in the following groups: Ni 10 20 30 40. 50 60 70 80 90 Cu Alloy group Cu' per cent Zn wt. per cent COPPER WEIGHT PER CENT 18ctA: 6to11 5to6 18 ct B: 31 to 33 5 to 6 Fig. 9 Projection on the room temperature plane of the gold-topper-nickel ternary phase diagram of 14 ct A: 50 to 54 9 lome isothermal solid-state boundaries of the im- 14 ct B: 66 to 68 9 miscibility field. After (9) 14 ct C: 66 to 68 6 lO ct A: 50 to 54 12 lO ct B: 66 to 68 12 10 ct C: 66 to 68 9 the B and C alloys occur at the right end at com- paratively high values of Cu'. As a rule, the zint con- In Figure 11 the A alloys occur at the left end of the tent increases with decreasing caratage. Also at both bold segments at comparatively low values of Cu' and 14 and 10 carat A, B and C alloys occur within the 129 18 CARAT 14 CARAT 10 CARAT Cu, Wt. °/e Cu, Wt. e/ Cu, Wt. °/o 0 10 20 0 10 20 30 40 0 10 20 30 40 50 1300 1200 1100 1000 LIQUIDUS 501IDUS 900 w SOLID 800 SOLUTION á (Au,Cu,Ni) w 700 1- 600 500 IMMISCIBILITY (Au-Cu) 400 '(Ni -Cu) 300 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100 Cu, -1. Cu', °/o Cu', % Fig. 10 Schematie quasi-hinary sections at constant caratage of the gold-copper-nekel ternary phase diagram. The parameter Cu' is defined in the text same overall range of Cu' values, that is 50 to 68 per In the quasi-binary sections in Figure 10, it is clear cent whereas at 18 carat, the range is much lower at 6 that as nickel replaces gold in lower carat alloys, the to 33 per cent. At all caratages, the upper limit of Cu' liquidus temperatures rise to values that are not adap- is determined by the amount of topper that can be table to jewellery gold casting, also, the alloys move tolerated before the white colour becomes yellowish. deeper and deeper into the immiscible cc + (Ni-Cu) On the other hand, the lower limit of Cu' is determin- region where the alloys have very limited workability. ed by the metallurgical characteristics of the gold- It is for these reasons that in the historica) develop- copper-nickel system. ment of low carat white alloys from the early 19 1/2 Fig. 11 Relationship between the colour and composition of gold-topper-nickel alloys. Usual jewellery white gold alloys have compositions within the bold segments of the constant caratage lines through the diagram. Thus t0 90 all such alloys are suscepti- bom? 20 80 ble to solid-state decomposi- c 18Ct. tion into nickel-rich and 70 ^<o gold-rich phases J 2 Q- ° Q 40 60 tQ 14Ct. O 40 ' o 10 Ct. 1 2^ 70 1 30 ó IMMISCIBILITY SOLID «(Au-Cu)'a(Ni-Cu)g 80 1 SOLUTION 20 .^^5 c 1 10 1 YELLOW WHITE ERF c ^ TO RED Ni 10 20 30 40 50 60 70 60 90 Cu COPPER WEIGHT PER CENT 130 carat silver-nickel-zinc alloy, it was found that some Commercial Nickel-Based White Gold copper was necessary at 18 carat and much more at 14 Alloys and 10 carat in order to produce workable jewellery Listed below are the compositions (weight per cent) alloys.
Load more

Recommended publications
  • 2000 Stainless Steels: an Introduction to Their Metallurgy and Corrosion
    Dairy, Food and Environmental Sanitation, Vol. 20, No. 7, Pages 506-517 Copyright© International Association for Food Protection, 6200 Aurora Ave., Suite 200W, Des Moines, IA 50322 Stainless Steels: An Introduction to Their Metallurgy and Corrosion Resistance Roger A. Covert and Arthur H. Tuthill* and why they sometimes do not. In most cases, selection of the proper stainless steel leads to satisfactory performance. COMPOSITION, NOMEN- CLATURE AND GENERAL PROPERTIES Most metals are mixtures of a primary metallic element and one or more intentionally added other ele- This article has been peer-reviewed by two professionals. ments. These mixtures of elements are called alloys. Stainless steels are alloys, as are brasses (copper + zinc), bronzes (copper + tin), the many alu- INTRODUCTION better understanding of stainless minum alloys, and many other me- Worldwide, in industry, in busi- steels, especially to the non-metal- tallic materials. In general, solid ness and in the home, metals called lurgist. metals and alloys consist of randomly stainless steels are used daily. It is Industries are concerned with oriented grains that have a well-de- important to understand what these integrity of equipment and product fined crystalline structure, or lattice, materials are and why they behave purity. To achieve these, stainless within the grains. In stainless steels, the way they do. This is especially steels are often the economical and the crystalline structures within the true because the word “stainless” is practical materials of choice for pro- grains have been given names such as itself somewhat of a misnomer; these cess equipment. However, before ferrite, austenite, martensite, or a materials can stain and can corrode intelligent decisions can be made mixture of two or more of these.
    [Show full text]
  • Dental Jewellery - a Review N
    Review Article Dental jewellery - A review N. Monisha1, Dhanraj Ganapathy2, P. Sherlyn Sheeba3*, Naveen Kanniappan1 ABSTRACT Today, people are becoming increasingly self-conscious about their appearance and smile. Intraoral jewellery has nowadays gained popularity and is slowly becoming a trend, but this fashion tagline is also associated with some serious health risks. The different jewellery in use today are lip studs, lip rings, tooth rings, grill jewellery, dazzlers and twinkles, veneer jewellery cheek studs, etc. There is an age-old history for dental jewellery as it was considered as a symbol of religion, tribe, culture, and sex. These accessories though are said to enhance beauty cause problems such as increase in plaque levels, inflammation of the gingiva and/or recession, decay, defective occlusion, and metal allergy. There are also some life-threatening complications such as airway obstruction due to aspiration, bleeding, erythema, and endocarditis. If there is a usage of unsterile instruments, it can act as a vector in the transmission of communicable diseases such as hepatitis, tetanus, and tuberculosis in susceptible patients. This review highlights the prevalence, complications, and side effects of dental jewellery. KEY WORDS: Dazzlers, Endocarditis, Gems, Hemorrhage, Intraoral jewellery, Ludwig’s Angina, Oral piercings, Twinkles INTRODUCTION niobium, or even plastic may be used.[4] A majority of complications are also associated. All body “Beauty lies in the eyes of the beholder,” is the famous piercings present a risk of infection and cause pain.[5] saying. The need and want for beauty has prevailed Complications that most commonly occur related to since ages. Our ancestors and religious rituals based the jewellery include aspiration, allergy or permanent on traditions, earlier defined beauty.
    [Show full text]
  • The Neolithic Copper Melting Crucibles from Switzerland
    In: A. Shortland, I. Freestone and Th. FromRehren mine (eds) to microbe 2009, From Mine to Microscope, 155-162 155 Chapter 15 From mine to microbe – the Neolithic copper melting crucibles from Switzerland Th. Rehren1 Abstract The occurrence of chalcopyrite in several late Neolithic crucibles from NW Switzerland and SW Germany has been variously interpreted as indicating evidence for local copper smelting, or being due to post-depositional phenomena. This study uses optical microscopy and a discussion based on textural and micro-stratigraphical arguments to demonstrate that chalcopyrite is a late formation and not indicative of copper smelting. This has significant implications for the technological and archaeological interpetation of these finds, but also illustrates the potential of image-based studies in science-based archaeology. Introduction these cultures back into line with their neighbours. The emergence and spread of metallurgy in Europe Only after a further half a millennium or so metal- is a major concern of archaeological and archaeo- lurgy emerges again in Central Europe, heralding the metallurgical research. In the 1960s scholars such as beginning of the Bronze Age throughout the Contin- Renfrew and Branigan focused their attention – and ent. This time, it is a broad and sustained develop- consequently that of others – on the role which metals ment with no particular emphasis on the Swiss or have played in the development of stratified societies southwest German regions. and the emergence of elites, showing off with their It is against this background that the crucible access to these new materials. The Balkans and fragments of the Pfyn culture have attracted attention Western Asia are now both known to have had for more than a century, having been found at a wide metallurgically competent Neolithic cultures, and range of sites and representing certainly several issues of technology transfer and autochthonous dozen different vessels.
    [Show full text]
  • The Magazine 2020-2021
    THE MAGAZINE 2020-2021 ITALIAN grace Inspired by Venetian lace, Buccellati’s Macri collection is elegant, everyday wearable sophistication. Hinged cuff bracelets in 18k white gold with black DLC treatment, 18k white gold and 18k yellow gold. Ring in 18k white gold with black DLC. Earrings in 18k yellow gold. Opposite page, eternity rings, Rombi Eternelle, Ramage Eternelle and Pizzo Venezia Ertenelle. 4 KERNS magazine I S S U E N U M B E R 5 These pages are just a taste of what you will find at Kerns Fine Jewelry. Call for an appointment to come in or for us to assist you virtually. Dear Friends, This has been quite a year! Even though 2020 has had its challenges, Be Part we are thankful for all the good things... family dinners, reduced of Our commutes and time to reflect are among a few. We have all become creative problem solvers and are stronger than we ever thought we Story could be. We miss shaking hands and giving hugs, but those will return in due time. Our new and improved normal will be unlike anything we could have fathomed and hopefully we won’t take all the little things for granted. You may have noticed a few changes at Kerns this year. We, like all of you, have adapted to our “new norm”. We are now open by appointment only, so please call us to schedule a time to come in. This new protocol felt strange at first, but now it feels better than #MyKernsMoment previous practices. We can space appointments throughout the day, Don’t forget to tag us on your social media plan ahead for your visit, and be more efficient with your time.
    [Show full text]
  • Oral Piercing – Pain Or Pleasure?? a Review Article
    IOSR Journal of Dental and Medical Sciences (IOSR-JDMS) e-ISSN: 2279-0853, p-ISSN: 2279-0861.Volume 13, Issue 10 Ver. I (Oct. 2014), PP 20-26 www.iosrjournals.org Oral Piercing – Pain Or Pleasure?? A Review Article Dr. Nitin Agarwal1, Dr. Haider Iqbal2, Dr. Kirti Agarwal3, Dr. Saurabh Mathur4, Dr. Siddharth Saurabh5, Dr. Ankit Saha6 1(Department of Oral Medicine & Radiology,Sardar Patel Post Graduate Institute of Dental and Medical Sciences,India) 2(Department of Oral Medicine & Radiology,Sardar Patel Post Graduate Institute of Dental and Medical Sciences,India) 3(Department of Pedodontics & Preventive Dentistry, Saraswati Dental College, India) 4(Department of Oral Medicine &Radiology,Saraswati Dental College, India) 5(Department of Oral Medicine and Radiology,RKDF Dental College, India) 6(Department of Oral Medicine & Radiology,Sardar Patel Post Graduate Institute of Dental and Medical Sciences,India) Abstract: Oral piercing is a popular trend, but this fashion statement comes with some serious health risks. The oral and perioral piercing has a long history as part of religious, tribal, cultural or sexual symbolism. Nowadays there is a high incidence of oral and perioral piercing in the adolescent population. Oral and perioral piercing involve the insertion of jewellery into the tongue, lip, cheek, frenum, uvula or other parts of the mouth. This paper covers some of the commonly and uncommonly encountered complications related to oral piercing. Keywords: oral piercing, body art, oral jewellery I. Introduction A Systematic review of the scientific literature was done and a database of indexed journals (Pubmed, Science direct and Ovid) and search engines like google, was searched.
    [Show full text]
  • Investment Casting Or the Lost Wax Process
    Investment Casting or The Lost Wax Process Apecs Investment Castings was founded in 1963 and is now situated in the Melbourne suburb of Burwood where we have been since we outgrew our Canterbury factory in August 1987. The company name (APECS), stands for Anthony Philip Eccles Casting Service. Investment is a type of plaster that we use in our process of reproducing multiple copies of an original master pattern which is usually supplied to us by our customers. This is a classic 18ct yellow gold emerald and diamond ring taken from the Apecs catalogue. The next series of photos will show the steps involved in producing multiple copies of this ring. An original master pattern is designed and fabricated by our customers and supplied to us to reproduce in the quantities and metals of their choice. It is important to ensure that the master is made as accurately as possible and to pay particular attention to the finish of the master pattern. The better the quality of the master pattern the better the casting result. The finished master pattern ready for the caster. A picture of the master pattern is drawn and a mould number is allocated for identification. When the customer wants to reorder he quotes the mould number for the pattern he wants. A sprue is soldered onto the pattern. This sprue enables the pattern to be easily located in the mould and will provide the path for the wax to be injected into the rubber mould. To make a mould the master pattern is placed between sheets of uncured vulcanising rubber.
    [Show full text]
  • The Evolution of Engineering Materials
    Paper ID #20611 The Evolution of Engineering Materials Dr. Amber L. Genau, University of Alabama at Birmingham Dr. Amber Genau is an assistant professor in the Materials Science and Engineering Department at the University of Alabama at Birmingham. She received her B.S. and M.S. from Iowa State University and Ph.D. from Northwestern University, all in materials engineering. Before coming to UAB, Dr. Genau spent two years as a guest scientist at the German Aerospace Center in Cologne, Germany, working on metal solidification and microstructural characterization. She is particularly interested in broadening participation in engineering and providing international experiences and perspectives to undergraduate students. c American Society for Engineering Education, 2017 The Evolution of Engineering Materials Abstract This paper describes the development of an upper level engineering elective entitled “The Evolution of Engineering Materials.” The course considers how the discovery of new materials and the ability of process materials in new ways has influenced the course of history, shaping both human societies and their surrounding environments, from the Stone Age to the Modern Era. Students become familiar with a variety of still-relevant technical content through the consideration of historical activity, from smelting and coking to polymerization reactions and cross linking. The course addresses a variety of ABET outcomes while also supporting the development of global competency through an increased appreciation of world history. Although this course was developed for and taught in the context of a three-week study abroad trip to Europe, the engaging and accessible nature of the content could also make it valuable as a service course for non-engineering majors.
    [Show full text]
  • M Have Certain Distinctive Properties Which Seem to Have Appealed To
    OUP UNCORRECTED PROOF – FIRSTPROOFS, Fri Dec 05 2014, NEWGEN !"#$%&' )* !"# $%&'( )#(*+,-&. */0 123&#''%-/' -4 5-6%*+ 8-,#& +,-.&' /&01, 2#%"#'34& 5#-.&' I!"#$%&'"($! M&%#-6 have certain distinctive properties which seem to have appealed to European Neolithic and later communities: brilliance, magical transformations behind their crea- tion, and potential for re-melting, re-casting, and re-modelling. 7ey were also valued for their colours: gold for the sun, high on the horizon, copper for the setting sun or the blood of life, and silver for the moon. In the formative years of metallurgy, copper and its ores appear to have held primarily aesthetic roles as cosmetic colours, beads, and other personal adornments. 7ey are likely to have been recognized as rare and precious, and were later mobilized in social di8erentiation. 7e adoption of metals altered economies and social relations, and triggered cra9 specialization. 7e roots of social di8erentia- tion were already present in some Neolithic communities, yet the uneven distribution of metal ores, like certain types of stone already, became elements in long-distance exchange networks and eventually trade. 7is paper attempts to go beyond simplistic ideas of metals in social strati:cation: it presents a more complex picture, outlining sim- ilarities and di8erences geographically in the presence and role of metallurgy during an early, middle, and late Copper Age. 03_3-part.indd 673 12/5/2014 7:57:19 PM OUP UNCORRECTED PROOF – FIRSTPROOFS, Fri Dec 05 2014, NEWGEN ;<= /&01, 5#-.&' T)* E+#,(*-" M*"+,,&#./ (! E&#$0*: A N*+# E+-"*#! O#(.(!2 The origins of metals can be found in the zone from which farming and animal husbandry came: the so-called ‘Fertile Crescent’ and adjacent Anatolia, the west- ernmost protrusion of Asia, comprising the majority of modern-day Turkey.
    [Show full text]
  • Carat Weight It's the Old Quandary. Is Bigger Better? Size Is Sought After, Naturally; but Overall Quality Counts in the Stretch
    Carat Weight It's the old quandary. Is bigger better? Size is sought after, naturally; but overall quality counts in the stretch. This balance of size and quality makes up much of the art of a professional gem cutter. It is the cutter's job to produce a gorgeous diamond while giving the consumer the highest CARATAGE for his or her money. Caratage means CARAT, the measurement used to weigh a diamond. The word carat is taken from the perfectly matched carob seeds that people once used in ancient times to balance scales. So uniform in shape and weight are these little seeds that even today's sophisticated instruments cannot detect more than three one-thousandths of a difference between them. Don't confuse it with KARAT, the method of determining the purity of gold. What's The Point? One Carat= 200 milligrams, or 0.2 grams. 142 carats adds up to one ounce. Carats are further divided into points. Carat Weight point system What does all this mean, and how does it work? The price of a diamond will always rise proportionately to the size of the stone. Larger diamond crystals are more rare and have a greater value per carat. So, a one carat diamond of a given color and clarity will be much more valuable than 2 one half carat diamonds of equal quality. Cut As the single human contribution to a polished diamond's beauty, cut is perhaps the most important, yet most over-looked, of the Four Cs of diamond quality. How does cut affect a diamond's value and beauty? A good cut gives a diamond its brilliance, its dispersion, its scintillation-in short, its life.
    [Show full text]
  • Transformative Copper Metallurgy in Chalcolithic Cyprus: a Reappraisal Bleda S
    Antiquity 2021 Vol. 95 (381): 670–685 https://doi.org/10.15184/aqy.2020.171 Research Article Transformative copper metallurgy in Chalcolithic Cyprus: a reappraisal Bleda S. Düring1,*, Sarah De Ceuster2, Patrick Degryse1,2 & Vasiliki Kassianidou3 1 Faculty of Archaeology, Leiden University, the Netherlands 2 Earth and Environmental Sciences, KU Leuven, Belgium 3 Archaeological Research Unit, Department of History and Archaeology, University of Cyprus, Cyprus * Author for correspondence: ✉ [email protected] The extraction and smelting of the rich copper ore deposits of Cyprus and the manufacture of copper objects on the island are thought to have begun dur- ing the Philia phase (c. 2400–2200 BC). Here, the authors present the results of lead isotope analysis undertaken on Late Chalcolithic (2900–2400 BC) metal objects from the site of Chlorakas-Palloures. The results facilitate a reassessment of the timing of the start of transformative copper technologies on Cyprus and the re-evaluation of contemporaneous copper artefacts from Jordan and Crete previously suggested to have been consistent with Cypriot ores. They conclude that there is no compelling evi- dence for transformative metallurgy in Chalcolithic Cyprus. Keywords: Cyprus, Chalcolithic, Philia phase, archaeometallurgy, copper, lead isotope analysis Introduction Cyprus was a major producer of copper in antiquity, and, as a consequence, the metal and the island toponym (from the Greek ‘Kúpros’) became synonymous (Kassianidou 2014). The question of when and how copper production and metallurgy started on the island, however, has proven difficult to answer. The earliest references to Cypriot copper exports date to the nineteenth to seventeenth centuries BC, occurring in cuneiform texts from Mari and Alalakh —both in the Northern Levant—and from Babylonia (Muhly 1972; Knapp 1996).
    [Show full text]
  • The Metallurgy of Some Carat Gold Jewellery Alloys
    The Metallurgy of Some Carat Gold Jewellery Alloys PART I — COLOURED GOLD ALLOYS Allen S. McDonald and George H. Sistare Handy & Harman, Fairfield, Connecticut, U.S.A. The classification of gold alloys in terms of caratage and colour provides no guidance as to the properties and working characteristics of the many carat gold alloys used in jewellery fabrication. Logical relationships do exist, however, between the composition, metallurgical structure and properties of such alloys, and these emerge from a study of the phase diagrams of the alloy systems involved. Part I of this review deals with coloured gold alloys. Part II will discuss their nickel containing counter- parts and will appear in the next issue of Gold Bulletin. Most carat gold for jewellery falls into one or other Three quasi-binary vertical sections of the ternary of two major categories, the coloured gold alloys diagram at constant gold contents characteristic of based on the gold-silver-copper or the gold-silver- jewellery alloys (10, 14 and 18 carat) are schematical- copper-zinc system and the white gold alloys. ly represented in Figure 4 where the parameter used Although many coloured gold alloys contain zinc on the abscissa is defined as: (from less than 1 to about 15 weight per cent), it is Ag wt.% valid to introduce this group in terms of the gold- Ag' = x 100 (per cent) silver-copper ternary system, from which all of the Ag wt.°Io + Cu wt.% alloys inherit certain fundamental metallurgical characteristics. After establishing these, the effects of Gold-silver-copper and gold-silver-copper-zinc- zinc will be introduced, and it will then be seen that alloys can be logically classified and discussed in in the amounts used this element does not change terms of two parameters, namely the caratage or gold these characteristics in kind but rather interacts to content and Ag'.
    [Show full text]
  • Introduction to Precious Metals 1 / Introduction
    Introduction to precious metals 1 / introduction Introduction to Precious Metals Metallurgy for Jewelers & Silversmiths Mark Grimwade Introduction to precious metals Introduction to Precious Metals Metallurgy for Jewelers and SIlversmiths by Mark Grimwade Copyright 2009 Mark Grimwade Brynmorgen Press Brunswick, Maine 04011 USA www.brynmorgen.com ISBN: 978-1-929565-30-6 First printing Editors Tim McCreight All rights reserved. No part of this publication Abby Johnston may be reproduced or transmitted in any form Illustrations Michael Deles or by any means, electronic or mechanical, Proofreading Jay McCreight including photocopying, recording, or any storage Index Margery Niblock and retrieval system except by a reviewer who wishes to quote brief passages in connection with a review written for inclusion in a magazine, newspaper, web posting, or broadcast. [ iv ] Introduction to precious metals Table of Contents Introduction xi Chapter 1 Physical Properties of the Precious Metals 16 Chapter 2 Mechanical Properties of the Precious Metals 26 Chapter 3 Chemical Properties of the Precious Metals 39 Chapter 4 Occurrence, Extraction, and Refining 44 Chapter 5 Alloying Behavior 56 Chapter 6 Principles of Solidification 72 Chapter 7 Principles of Working and Annealing 83 Chapter 8 Silver and Its Alloys 91 Chapter 9 Gold and Its Alloys: the Karat Golds 100 Chapter 10 The Platinum Group Metals and Their Alloys 116 Chapter 11 Melting, Alloying, and Casting 126 Chapter 12 Working and Annealing Practice 144 Chapter 13 Joining Techniques 165 Chapter 14 Electroplating and Allied Processes 180 Chapter 15 The Use of Powder Metallurgy in Jewelry Manufacture 193 Chapter 16 Surface Decoration and Other Decorative Techniques 200 Chapter 17 Assaying and Hallmarking 207 [ [47 v ] ] Introduction to precious metals Foreword If you work with precious metal, you need to read this book.
    [Show full text]