1 NOVEMBER & DECEMBER 2019 Now in its 15th year No Stone Unturned Merry Christmas & Happy New Year

Mediterranean Sea

Camping styles

KEN 1

Our club offers tuition in the lapidary arts of cutting and polishing cabochons, faceting stones and crafting silver jewellery. Sign up for these courses at the front counter for 2020!.

Above, Sylvia with her latest silver class Above: Robbie, finding sapphires ladies. Read his report inside. Left, Mike hands Amanda her certificate for cabbing. 2 CONTACT INFORMATION: WE WISH TO THANK THE FEDERAL Phone: 0450 185 250 MEMBER FOR LEICHHARDT, HON. Email: [email protected] WARREN ENSTCH, FOR FACILITATING THE Postal Address: PO Box 389, Westcourt. 4870. NQ PRINTING OF THIS MAGAZINE. 129 Mulgrave Road (in the Youth Centre Grounds) MANAGEMENT COMMITTEE MEMBERS: CLUB HOURS:

President: Michael Hardcastle Monday 4:00pm to 9:30 pm

Vice-president: Mike Rashleigh Wednesday *8:30am to 12:30

Secretary: Jan Hannam *1:00pm to 4:00pm

Treasurer: Joe Venables Saturday *9:00am to 1:00

Assistant Secretary: Allan Rose *12:00pm to 4:00pm

Assistant Treasurer: Richie Williams Workroom fees are $4 per session or part

Extra Members MC: Tammi Saal thereof and must be paid before session begins. The Club provides tuition in cabbing, faceting, OTHER PERSONNEL: silver-smithing and lost wax casting Purchasing Officer: Jan Saal Specimen Curator: David Croft Note: The Club is closed for gazetted holidays Specimen Testers: David Croft, Vic Lahtinen, only and open on other club days Trevor Hannam GENERAL MEETINGS: Cabochon Advisors: Jodi Sawyer Faceting Instructors: Jim Lidstone, Joe Ferk, General meetings are held on the 1st Saturday of Trevor Hannam each month. When this is a public holiday, the Silver Instructors: Sylvia Rose, Jan Saal meeting is deferred until the following Saturday. Machinery Curators: volunteers needed Note: Your Attendance at General Meetings Gem Testing: Vic Lahtinen, Trevor Hannam ensures that your voice will be heard when it Librarian: David Croft comes to making decisions concerning the Facebook Admin: Tammi Saal, Peggy Walker running of the club. Webpage Admin: Richie Williams, John Heenan QLACCA Delegate: Bill Reece CLUB PURCHASING POLICY: Youth Centre Rep: Bill Reece If you wish to purchase something on behalf of the Field Trip Advisors: Allan Gale, Craig Walker, club, please notify the purchasing officer, Jan John Heenan, Leigh Twine Gem Festival: Trevor Hannam, Michael PLEASE CONSIDER CONTRIBUTING MATERIAL Hardcastle, Allan Gale, for “No Stone Unturned”. Tammi Saal, Mike Rashleigh Auditor: Carey Accountancy Magazine Editor and Publisher: Jeanne Mora Safety Officers positions vacant The Editor reserves the right to choose and edit all Club Banking details for anyone wishing to pay material featured in this magazine. membership fees electronically: Although all care is taken to ensure the Bendigo bank Acc: 165026436 BSB: 633 000 accuracy of the material herein, the Editor Gem Festival and Membership does not accept responsibility for any inaccuracies which may inadvertently occur. 3

PRESIDENT’S REPORT:

Hello Everybody

Well what beautiful weather we have been experiencing in the Cairns region. We have only just started using the air conditioning units, due to the mild temperatures this year. Welcome to our new members. It’s great to see you using the facilities and having fun learning the skills.

Our Christmas Party Feast is on December 7th after the general meeting which will start one hour earlier at 11:00am. All members and friends are welcome. Could everybody attending please fill in the list on the notice board. Thank you! It will assist Betty in purchasing the right quantity of ham and chicken for our merry Christmas gathering.

John Heenan has been appointed as an additional Webpage Administrator. Thank you so much, John, for volunteering for this technical position. John has been busy working behind the scenes developing a new Webpage. John is encouraging all members to get involved, register and participate in adding to and developing the new Webpage. John advises that the easiest way to get to the club webpage is to google “cairns lapidary” and choose the link in large letters that says “Cairns Mineral and Lapidary Club”.

Thank you to Jean McGuigan and family who have kindly donated rock specimens that have enhanced the club’s display. Jean also donated a lapidary work station and some rocks which are available for members to purchase. This donation was much appreciated.

The club has also purchased a second-hand flat lap machine . Please check with instructors before using the flat lap.

Thank you to all our instructors who have been busy sharing their knowledge. I’m sure it is much appreciated.

Betty has agreed to monitor the kitchen again and to purchase supplies. Thank you Betty for volunteering for this position. A big thank you to the Management Committee who work as a great team volunteering their time and knowledge to assist in the efficient operation of the club. Remember there are many mem- bers working in the background, ordering stock, purchasing equipment, purchasing equipment, maintain- ing machinery, making homemade cakes to share at smoko, Webpage. Facebook page, compiling , emp- tying bins, vacuum cleaning etc etc. The more members who volunteer, will add up to making our club a stronger organisation. Thank you everybody, especially Jeanne the editor of “No Stone Unturned” without you we would not be reading this article.

Just a reminder, your club membership expires on 31th December and due to insurance conditions, you will not be permitted to use the workrooms if your membership has expired.

I wish you all a safe and merry Christmas and very happy New Year.

Michael

4 DATES TO REMEMBER AROUND NOVEMBER THE 2 Club General Meeting 12:00 noon CLUB 2 QLACCA Christmas dinner Our thoughts are with all members and their 2 &3 Bundaberg Gemfair held at the Multi families who are unwell. Purpose Centre, Bundaberg East Many Happy Returns to all members celebrating a 2&3 Illawarra Lapidary Club Jewellery Gems birthday in November: and minerals Festival held at the Ribbon A warm welcome to all our new club members. wood Centre. Adam Brown, Daimen Hampson, Jacky Arnott, Jedess 2&3 Geelong Gem and Mineral Gem Show Hudson, Stacey Carseldine, Walter Sneesby held at Geelong West Town Hall New members, please keep in mind that our club sells most lapidary requirements at very competitive prices. 10 Sunday Slog 9:00 to 12:00

Ask at the counter. 16 Management Committee Meeting

23 Trevor’s Demonstration of Electroform ing Christmas Party DECEMBER 1 Redcliffe gem Show Venue to be When: Saturday 7th Dec announced Where Club Rooms 7 CLUB CHRISTMAS PARTY following the What you need to do:- General Meeting which starts at 11:00 this 1. Bring a plate of Christmas time

goodies 12 Club closes after this session for the 2. Sign up on the notice board & Christmas recess.

say how many of you are coming 25 A Very Happy & Safe Christmas to and what food you are bringing Everyone.

3. BYO booze if you want to (no glass please… Youth Centre directive)

4. Get into your best party gear

5. Put on your best smile and party mood 6. Prepare to party with our great fellow members.

Remember we reopen on 15th January 2020

5 Some different tutorials for you to try 6

Sedimentary Rocks

Most of he rocks on the surface of the earth are sedimentary Sedimentary rocks are named as such because they were once sediment. Sediment is a naturally occurring material that is broken down by the processes of weathering and erosion and is subsequently naturally transported . Sedimentary rocks form through the deposition of material at the Earth’s surface and within bodies of water. There are 7 main groups of sedimentary rocks.

• clastic sedimentary rocks — small rock A conglomerate — a rock made from cemented gravel. Image via fragments (many are silicates) that were transported Earth Physics Teaching. and deposited by fluids (water, bed flows). These rocks are further classified by the size and composition of the clastic crystals included in the sedimentary rocks (most often quartz, feldspar, mica and clay). • conglomerates (and breccias) — conglomerates are predominantly composed of rounded gravel, while breccias are composed of angular (sharper) gravel. • sandstones — as the name says, it’s a rock made from many-sand-sized minerals and rock grains. The most dominant mineral in sandstone is quartz because it is the most common mineral in the Earth’s surface crust. • mudrocks — again, the name says it all — they’re rocks made from solidified mud. They typically contain very fine particles and are transported as suspended particles by turbulent flow in water or air, depositing once the flow settles. • biochemical rocks — you’ll probably be surprised to find out that most limestone on the face of the Earth comes from biological sources. In other words, most limestone you see today comes from the skeletons of organisms such as corals, mollusks, and foraminifera. Coal is another example of biochemical rock. • chemical rocks — these rocks include Below: An old, red sandstone. Image via Ian Hopkinson. gypsum and salt (halite) and are formed mostly through water evaporation

There are also other types of specific sedimentary rocks — for example, the ones formed in hot springs. Most of the solid surface of our planet (roughly 70%) is represented by sedimentary rocks, but if you go deep enough beneath the Earth’s surface, there are plenty of igneous and metamorphic rocks to be found. As mentioned with biochemical rocks, fossils can become rocks in time. You can actually have entire mountains made up from reefs as you can see in the diagram on the next page. 7

This entire mountain in Romania was formed based on a coral reef. Image via MP Interactive Some common sedimentary rocks are:

• argillite

breccia • Left: Rock Salt Yes, salt is a mineral • chalk — and it can be quite beautiful. In this context, it’s called halite and can • chert be classified as a sedimentary rock • claystone

• coal

• conglomerate Left: Conglomerate: The specimen • dolomite shown is made up of chert and lime- stone clasts bound in a matrix of • limestone sand and clay. Below is a close up • gypsum picture of it. • greywacke • mudstone • shale • siltstone • Turbidite This is just scratching the surface — you could spend a lifetime studying rocks and still be surprised. But I hope that for your general knowledge or to impress some friends (or if you’re considering starting geology), the information here was useful and interesting to you.

Now you have read this, you will soon realise that to correctly identify a specimen you have unearthed is a fairly complex procedure. You will need to determine the properties of your specimen. 8 Now you have an idea of how rocks are recycled over millions of years by the movement of the tectonic plates, powered by the convection currents in the Earth’s mantle, it’s time to find out how scientists identify the different minerals, which occur in two or more varieties in any rock. If a mineral is allowed to grow unhindered, it will develop an characteristic three-dimensional shape. Unfor- tunately, for the lapidary, minerals hardly ever form good crystals . When a rock forms, all the chemical components organise themselves into minerals, which grow crammed up against one another. Only if a min- eral can develop in a fluid, uncluttered by other solid matter, does a good crystal form. Below left are the 7 crystalline shapes , showing their axes. It is the crystalline shape of a mineral or gemstone which determines its cleavage. MINERAL IDENTIFICATION Axises Crystal Shape Mineral Example If a mineral does not have a distinctive crystal shape to reveal its identity, there are a number of other techniques which can be used in order to make an identification. HARDNESS Different minerals have different hardnesses, and these are measured by Mohs scale (below). Minerals with a higher number will scratch a mineral with a lower number, thus talc (1) can be scratched by any of the other minerals on the scale and a diamond (10) will scratch every other mineral on the scale (below Moh’s hardness sale) 9

Mohs Scale is not very practical as most lapidaries will not have the relevant minerals with them out in the field so they can use the following common things which they may have with them, to get a rough idea of the hardness of their find. For example ay find that can be scratched by a fingernail is certainly not anything over 3 on Moh’s Scale and anything that can cannot be scratched by a steel file has a hardness of more than 6.5n etc. 2.5 fingernail 4 copper coin 5 glass 5.5 penknife 6.5 steel file STREAK: This is not the same as the colour of the mineral. (That colour is usually caused by impurities in the mineral). The streak is the colour left when the specimen is drawn over an unglazed white ceramic tile (the edge of a broken china cup will do). This is often a reliable guide to the specimen’s composition. For example, hematite, a blackish mineral, will make a cherry red streak and pyrites which is a golden colour makes a greenish or brownish black streak. SPECIFIC GRAVITY: This is the weight of the mineral compared with the weight of an equal volume of water. To accurately meas- ure specific Gravity, a specimen is weighed in air, then it is immersed in water and the water displaced is caught and weighed. Dividing the dry weight of the specimen by the weight of the displaced water will give the specific gravity. Measuring specific gravity is definitely not something you would do out in the field but you can get some idea of this by “hefting” the specimen. If it feels heavy for its size it probably has a high specific gravity. Lead feels very heavy compared to its size when compared to the weight of the same sized piece of scoria. FRACTURE: (an important property for factors) Minerals with distinct cleavage plains will split along them when broken. Other minerals will break randomly, while some may give a distinctive type of break of fracture. Conchoidal fracture, pic- tured at right, is quite notable producing concentric patterns of ridges reminiscent of some sea shells. Quartz shows a conchoidal fracture. Hackly fracture is a jagged surface as produced in some metals. Native metals (eg native silver) usually have a hackly fracture. Earthy fracture gives a powdery appearance. Meerschaum , a magnesium silicate, shows earthy fracture. LUSTRE: Lustre, in mineralogy, is the appearance of a mineral surface in terms of its light-reflective qualities. Lustre depends upon a mineral’s refractive power, diaphaneity (degree of transparency), and structure. Variations in these properties produce different kinds of lustre, whereas variations in the quantity of reflected light produce different intensities of the same lustre. The kinds of lustre are usually described as follows (the prefix “sub-,” as in submetallic, is used to express imperfect lustre of the kind): metallic (the lustre of metals—e.g., gold, tin, copper; minerals with a metallic lustre are usually opaque and have refractive indices near 2.5); adamantine (nearly metallic lustre of diamond and other transparent or translucent minerals with high refractive indices [between 1.9 and 2.5] and relatively great density—e.g., cerussite and other compounds of lead); vitreous (the lustre of broken glass—the most common lustre in the mineral kingdom; it occurs in translucent and transparent minerals with refractive 10 indices between 1.3 and 1.8, as in quartz); resinous (the lustre of yellow resins—e.g., sphalerite); greasy (the lustre of oiled surfaces—e.g., nephe- line, cerargyrite); pearly (like pearl or mother-of- pearl—e.g., talc; surfaces parallel to a perfect cleavage exhibit this lustre, which results from the repeated reflections from minute cleavage cracks); silky (like silk—e.g., satin spar; minerals with a fibrous structure have this lustre); dull, or earthy (without lustre—e.g., chalk). Right: examples minerals with a different lustre

ANLYSING MINERALS WITH LIGHT: If you slice a rock or mineral thinly enough it is transparent and, mounted on a glass side, it can be examined through a special kind of microscope. This technique is the main one used by geologists to identify minerals & rocks but will not be discussed here. REFRACTIVE INDEX: Light passing from one medium to another is refracted, or bent, towards the denser medium. (That’s why when you stand a stick in water, it appears to bend...water is denser than air.) The amount by which a ray of light refracted on entering a mineral is called its refractive index. It is found using a refractometer. Light (1) enters through the rear of the refractometer through an opening (1a) in (or before) which a yellow sodium filter can be A basic refractometer placed. It then hits a mirror (2) which transmits the light to the centre of the hemicylinder (3). This hemicylinder is made of high refractive glass (usually N-LaSF by Schott with a refractive index of ~ 1.88 at nD and a hardness of about 6.5 on Moh's scale). At the boundary between the hemicylinder and the gemstone (4), the light will be partially refracted inside the stone and partially re- flected in the hemicylinder (see below on Total Internal reflection). The reflected rays (5) will pass through a reading scale (6) and a lens (7) or a series of lenses, depending on the type of refractome- ter. The reflected rays hit a mirror (8) which directs the light to the ocular (9) and then outside the refractometer to your eye (11). The ocular (9) can slide in and out for better focus and is usually accompanied with a detachable polarizing filter (10). As the hemicylinder has a relative low hardness compared to most gemstones, care must be taken not to scratch it. That would ruin your refractometer, as optical contact between the gemstone and the cylinder would be impossi- ble and would give you false readings. 11 Total Internal Reflection

When light travels from an optically denser material (with higher in- dex of refraction) to an optically rarer material (with lower index of refraction), all light that reaches the boundary of the two materials will be either reflected inside the denser material or refracted into the rarer material, depending on the angle of incidence of the light.

For every two media in contact in which light is traveling from the denser to the rarer medium, the dividing line where either the ray of light is totally reflected or refracted is fixed and can be calculated. This dividing line is named the critical angle (ca). On the left you find an image showing the critical angle as the red line. When light reaches the boundary of the two materials at an angle larger than this critical angle (the blue line), the ray of light will be totally reflected back into the denser material. Light reaching the boundary at an angle smaller than the critical angle will be refracted out of the denser medium (and a small amount will be reflected) into the rarer medium (the green line). All light traveling precisely on the critical angle will follow the path of the boundary between the two materials.

N.B.: In this example, the light seems to come from 3 light sources, but the principle is the same when coming from a single point. In a hemicylinder, the incident and exiting ray always reach the boundary at a 90 degree angle when directed to the center. Refraction doesn't occur when a light ray is at 90 degrees to the boundary. A hemicylinder is used so there will be no refraction of the light entering nor leaving the denser material. The standard gemological refractometer can make use of this phenomenon because the reflected rays of light will appear as a light area on the scale, whilst the refracted rays are not visible (and therefore appear black). The light/dark boundary shown on the scale of the refractometer is a visible representation of the critical angle. The standard gemological refractometer thus measures the critical angle between the glass hemi-cylinder and the gemstone and plots that on a calibrated scale. This type of refractometer is hence better named a "critical angle refractometer".

Proper lighting is one of the key features when using the refractometer. Although one can get results using a white light source, the standard is monochromatic yellow light with a wave- length of about 589.3nm. This light source is historically used as it was easily produced by burning table salt in a candle (at a very low cost). All gemological refraction indices are based on the use of sodium light (or nD). For more information, see Fraunhofer. The use of different wavelengths can produce different readings. As the refractive indices of gemstones are meas- ured with an accuracy of 0.001 decimal, sodium light should be used. All gemological tables of refractive indices are produced using this light unless otherwise stated.

White light may be used for single refractive gemstones or to obtain a first impression. One should look for the boundary between the green and the yellow of the allochromatic white light source.

However, for double refractive gemstones, one should then switch to a sodium light source, simply for the reason that the double refraction readings in white light may easily overlap and it would be impossible to get a correct 12 reading. And of course the boundary between the lighter and darker areas is better defined, making the reading easier to take. Always buy a refractometer with either a sodium filter or a sodium light source.

For accuracy, using a refractometer is a complicated process, one which will not be included here.

A pretty pattern to facet over the Christmas break

13 Continuing Trevor’s Story from the October edition of No Stone Unturned THE STORY OF THE GOLD MINE “PEG A CLAIM ” (a work of fiction) Part 2 “My map so far had been unquestionable and accurate and I was full of hope and expectations until, what should have been a mountain pass was nothing but desert, some wiry looking trees and a high mountain well in the distance. So much for treasure maps and being conned out of my money!

With nowhere else for us to go we headed west towards that solo mountain in the distance. Four days later we arrived at the base of the mountain where, to our surprise, we found a large lake of water. POISON! The water was undrinkable and there were many dead animals around its perimeter.

Then we found a soak was right next to the mountain base and the water was clear and sweet to drink. With plenty of game around we decided to investigate the mountain as it was a strange shape (like molten lava that had stopped in mid flow). Here were quite few caves in the mountain, and one was quite large and hard to reach. We cut down a few of the native trees and made a ladder to reach the entrance of the cave.

Within the cave was a small reef of GOLD! YAHOO!

A week later, we had dug up enough gold for us to purchase better equipment, stake a claim and sink a shaft into the mountain to see what was there. At this time Mr Black, my friend, was made a full partner in this venture.

In general, it took us a long time to get back to civilization, register a claim, cash in the gold and get all the equipment needed to for sinking a mine shaft into the mountain.

Fully rigged now with a team of horses and all our equipment, we headed out to our destination.

A couple of months later we arrived at that mountain, set up camp and began making a track right to the spot where we figure a shaft should be dug. It was hard work, digging, using explosives and boarding up the shaft which proved to be highly effective. The mine was now producing a good recovery of gold and showed signs of getting better and better.

The shaft was now down to the base level and the seams showed that hey were now heading into the moun- tain proper. Time to shut down the mine shaft and use some of the gold produced, to form an association. The new mine was named “The Hannam & Associates Mine ”. The old mineshaft was now abandoned and left derelict.

Today the mine is complete with a special Hot Air Gamma Engine all the way from England, running a large water pump and three head battery stamper, producing 150 kg of ore. It is the best the world has ever seen!

God bless Australia!

Yours truly, Trevor Hannam 14

They had to get divorced because of

religious differences.

He thought he was God but she didn’t.

They say diet and exercise are good for you but there’s one thing I want to know….who is this “they” and why don’t they keep their opinions to themselves?