sign in sign up
<<
Home , Carnelian, Jasper, Orbicular jasper

89089560213 Anthro 352 - Kenoyer Kenoyer,

Stone Beads and Makino b I1II1I111111111 " 11111111111111111111111111111111111· Techniques b89089560213a A BEADTIMELINE VOLUME I: PREHISTORY to ·1200cE A Resource for Identification, . Classific'ation and Dating.

BY JAMESW LANKTON, M.D.

JOYCE'DIAMANTI AND . JONATHAN M. KENOYER, PH.D. . PHOTOGRAPHY By,ROBERT K. LID, PH.D.

~3 stone beads and pendant. making techniques Jonathan M. Kenoyer

he large number and great vari­ ety of stone beads on the Bead T TImeline make their origins and manufacture ofspecial interest. Two factorS define the process: the characteristics of the raw material being used; and the effort that a beadmaker wishes to expend. Soft stones; such as talc or soapstone, can easily be carved, drilled and polished to produce a bead or pendant. Harder stones require different techniques, worked out over many . thouSands ofyears. In addition, the surface . of the stone can be painted, incised or . glazed to modify its natural appearance. The nature of the raw material and the processes of manufacture often contribute to the longevity of a bead and its overall cultural or economic value.

Raw Material Origins Each region of the world has distinct FIGURE 1: RAW MATERIALS FOR BEADS AND BE;ADS ILLUSTRATING MATERIALS. in order of their numbers: types of natural raw materials which limestone. fossiliferous limestone. orbicular . . banded . dyed agate. . coUld be used to create objects ofvalue for . . sardonyx. , grey steatite. talc, bloodstone. . . sodal.ite, . serpentine. rock crystal. smoky and rose . . . basalt with local as well as external trade. Human quartz bands. and . Photographs: J. Mark Kenoyer. communities have experimented with all varieties of rock to make beads or to use times, human communities have shown expose a wide variety of exotic raw mate­ as tools in the processing ofstone beads. a preference for materials that are rare rials, many of which have been sought . Grinding and polishing stones, as well·as and·exotic.. Generally speaking, rare after for making beads. drills, are made from specific types ofrock materials have more value than objects Rocks themselves, which are composed that are hard enough to modifY the surface made from commonly available stones, ofa number ofconstituent , have of other rocks. The Mohs' hardness scale except in situations where the common been used to rriake beads; examples include can be used to give an idea of the relative materials have been modified through basalt, a dark igneous rock; marble, the hardness of various rocks, with values complex technologies. metamorphic form of limestone; and ranging from I(talc) t~ IO(). A Each species ~f rock is formed through. lapis lazuli, a rock composed of calcite, . variety of raw materials commonly used for. very specific geological processes that pyrite, and the blue minerallazurite. . stone beadmaking is shown in Figure I. occur in distinct areas of the landscape More commonly,beadmakers have sought Selecting an appropriate raw material or the earth's mantle. Plate tectonics rocks with concentrations of minerals, for making a bead is the first of many create zones of tremendous pressure such as steatite, serpentine, chlorite, . stages where decisions are made by a and heat,. transforming the surrounding calcite, , and , in order .beadmaker. Many stone beads are made sedimentary and igneous rocks into of increasing hardness. In order to obtain &0 m rocks that have nat~ral features that their metamorphic counterparts. Rugged some crystalline , such as make them attractive, induding specific mountains form as these same forces , ruby, and , miners must colors, distinctive patterns; or the ease push up layers ofsediments and rock &om blast through tons of the surrounding .with which the stone can be modified the lowest levels 'of the earth's crust. Over matrix to find crystal veins or inclusions. and perforated. From the very earliest the years, these mountain rocks erode to Volcanic eruptions produce , stone beads and pendant n1.aking techniques Jonathan M. Kenoyer

a natural glass which comes in several Raw Material Preparation Shaping Bead Rougbouts colors and has often been used for making After collection, rocks must be prepared Some stone beads are made from natu­ beads. Among the most popular bead­ for manufacture through varioUs processes. rally shaped pebbles without any further making materials are the various forms Some rocks such as agate and chalcedony modification except to drill and sometimes of crystalline quartz, ranging from rock are dried in the sunEor months to remove polish the stone. However, most stone crystal th~ough the microcrystalline , any moisture prior to heating. The nodules beads are made by selecting a large block varieties ofchalcedony and banded agate, are then slowly heated to around 340 0 C of stone and breaking or sawing it into which form in hollow pockets ofmassive to drive off the intercrystalline water, smaller pieces, referred to as blocklets or volcanic lava flows. After millions ofyears making them easier to flake. Heating bead roughouts. Rocks such as agate and these agate nodules or geodes erode and also changes the color ofthe raw material. can be flaked relatively easily using collect in stream beds as massive gravel Rocks that are saturated with become a stone or various sizes of metal deposits. Colored and chert are reddish after heating in an oxidizing atmos­ ,. In India, beadmakers use the formed in limestone or other alluvial phere. If a rotkisheated ina smoky or technique of inverse indirect percussion, deposits that also eventually erode, expos­ reducing atmosphere it will turn darker as shown in Figure 2. An iron stake is set ing these very hard rocks for use as ~eads, and sometimes become black.,Jhterttional into the ground at an angle and the bead .or as will be discussed below, to make drill". coloring of rocks will be discussed below, chipper sits on the ground with one knee Each variety of ~ock has specific ft4tures but the coloring process actually begins bracing the stake. In one hand he holds ,that a beadmaker must take into account right from the first heating. While some a bead roughout and the other wields a as the bead is being processed. rocks become "softer" when heated prop­ hammer made with water buffalo honi erly, others can be made harder. Usually and a flexible bamboo handle. The bead Collecting and Mining this is done after the bead is finished and roughout is placed against the stake and The collection of raw materials depends the most common rock that is hardened the soft hammer is used to strike the bead . entirely on the type of rock being sough': by heating is talc or soapstone (steatite), roughollt against the stake to remove a 'and the geological processes that have which Can change in hardness from Mohs' flake without damaging the stone. affected the landscape. In many regions of 3 to Mohs' 5. Materials such as nephrite and j,adeite the world, the earliest beadmakers simply collected partially rounded pebbles from streams or beaches and then perforated them to produce a bead. Other rocks can be collected hom eroding cl.i..ffi; or hom exposures where they can be broken from the parent rock. One oftheearly methods for obtaining lapis lazuli and other rocks from massive formations was to build a fire against the rock and throw water on the heated surface to make it crack apart. Through experimentation with fire, people gradually came to understand how to modify rock in other ways. When the surface rocks were depleted, mining was developed to follow a vein ofdesired rock ~ ~rth. z deep into the Today mining is the ' ::1 ,major method for obtaining materials such FIGURE 2: left-hand photographs show inverse indirect percussion technique ofpreparing bead ~ blanks. Upper right shows sawing of agate with saw and abrasives. lower right shows prepa- f-< as carnelian, serpentine, talc, chert, jade, lOtion ofmaterial for microbeads, seen as strand. In middle are respec1ively from top to bottom: banded ~ turquoise and fine gemstones. agate roughouf. bead blank and pierced bead; carnelian roughout and finished bead. a:l stone beads and pendant making techniques Jonathan M. Kenoyer

do no! break very easily and must be sawn· as were the shell heishi beadspro'­ materials, it is now possible to make or ground into smaller pieces. Sawing duced in the American Southwest. extremely precise molds of bead perfora­ can be done with an abrasive sand and Even with modern grinding wheels, the tions that can then be examined under a blade,. using water as a lubricant . preparation ofstone beads requires consid­ the Scanning Electron Microscope. and coolant. In cultures that did riot have erable time and skill. Most beads are Experimental studies of perforation and metal tools, sawing was done with a individually shaped by hand and only drilling technology, uSing different types string or eVen a piece ofwood. The grains spherical beads can be produced with a of tools or drill bits have made it possible of hard quartz or emery in the sand minimum of handling. to differentiate the various perforation become embedded in the soft copper or There are many more techniques of techniques and correlate them to specific organic saw and gradually cut through preparing bead roughouts and bead blanks, time periods and to cultural regions, as the hard rocks. some ofthem unique to specificcultures. shown in Figures 3a, b. Many cultures do not necessarily use the . Short disk shaped and biconical beads . Bead Blanks most efficient technique since the prepara­ ?fcarnelian and agate reveal the use of a Bead roughouts are often processed again tion ~f beads may be part ofa larger social pecking technique that results in a rough to create various types offinal bead shapes event, and careful hand grinding may be hour-glass shaped perforation. Although which are called bead blanks. Some rocks a ritual event undertaken for only a few considerable effort has been made to repli­ are initially processed by fine chipping hours a day. cate this process it has not been possible using smaller punches and smaller ham­ to .reproduce the small carnelian beads that mers, but eventually most bead roughouts Perforation or Attachment were made in the Neolithic of South and are ground or carved to achieve the final The point at which a bead ·blank FIGURE 30: Chart of bead drills and resulting bead shape. Traditionally, grinding was becomes a bead or pendant is defined by perforations. Lower left and right are done by hand using a h~lfd or the grooving or drilling ofthe ornament respectively Scanning Electron Micrographs grinding stone. This process is to facilitate stringing. By taking a pointed of rubber casts of beads drilled by Indus and tubular drills. extremely time consuming depending on object and turning it back and forth it is si~ the and hardness ofthe bead material. possible to gouge or drill into a stone and @ 1 , i ~ , [ID I A long barrel shaped carnelian bead can eventually perforate it. While much of the [IIJ <3 rnJ "'" ~ 0 be hand ground iriabout four hours of earliest drilling was done by hand, the @ ® ® ~ continuous work by an expert, taking great use ofthe waS widespread by the ® 'D pecked chertfpsper tapered copper pointed stick care not to break the blank through exces­ . 4th millennium BCE, and is still one of tapered cylindrical or copper wire sive heat or pressure. Tiny beads that are the most efficient methods of drilling. toosmall to hold in the han4 are held by Perforations were usually achieved by ~ ~ .~. U 0 asmall wooden vise or attached to a drilling from both ends, with the hole Q wooden rod or dop stick using some form .meeting at the center ofthe· bead. Ifthe (ID CD:! large tubular ~fadhesive. Mter grinding one side, the drilling is properly centered, .it will pro- . fine 00 tubular LJ tiny bead is taken out ofthe vise and turned duce a smooth cylindrical or hourglass jasper Emeslite to" allow the other portion to be shaped. shaped perforation. long long tapered constricted Ariother technique for shaping tiny . The actual drilling ofthe bead blallk is . cylindrical cylindrlcaJ beads is to cut thin sheets of the rock and . one ofthe mostd~cult and critical steps CID break them into small squares or disks in beadniaking, and the specific type of that are then drilled in the center. These perforation used to make stone beads, drilled roughouts ~e strung on a cord or· whether by pecking or drilling,hastilrned 1%.1­ 5 wire so that many beads call be ground out to be an inforrilative detail ofancient ~ aild shaped at the same time. Neolithic that was never fully appreciated i micr~beads of lapis lazuli and carnelian by earlier scholars. With tbe ·invention of l:Q were prepared in this way, along with high quality silicone based impression '::£ stone beads and pendant making techniques Jonathall M. Kenoyer

West Asia.. In fact it was even difficult for ancient beadmakers since we find many beads that were broken in manufacture. Long and short tapered drills, made .by notching and steep retouch on chert microblades are found throughout the world, beginning in the earliest Neolithic period and continuing up through the Iron Age circa 1200 BCE in the Old World and much later in the New World. Some of these drills may have been used to perforate unfired steatite bead blanks, but most of them were probably used on shell, or wood. Some tapered s~one drills made ofchert or jasper bladders were modified into a more specialized form referred to as a «tapered cylindrical drill". These drills were

used to decorate and perforate softer stone, FIGURE 3b: Left-hand images show drilling with single and double diamond drills in , such as lapis lazuli, tutquoise, or limestone, India, and closeup of both types of drills. Right-hand images show drilling with single diamond and to perforate short beads of harder stone drill in Peshawar, Pakistan. The diamond chip is held in a hyperdermic n~edle. Carnelian bead perforated with this type of drill and its silicon cast replicates the perforation. such as agate or carnelian. This type of drill is found at sites throughout West Asia and samples ofsteatite suggest that long perfo­ some particles of or corundum in the Indus valley, and has a long history of rations were probably made using copper them. In Africa and the Mediterranean Use that begins in the Copper-Bronze drills rather than with stone drills. The many of the abrasive sands naturally con­ Age around 5500 BCE arid continues use of solid wood or copper drills with tained the harder minerals. By the late 3rd through to the beginning of the Iron Age. abrasive was the predominant form of millennium BCE the intention~l use of Constricted cylindrical drills have have drilling in East Asia and many parts ofthe '. corundum in western Asia greatly facili­ on:ly been reported frornthe Indus Valley New World. tated the perforation of hard stone beads. during the Harappan period (2600-1900 Tubular drills made from a reed or The use of tiny diamond chips for BeE). They have a long cylndrical shape bamboo have been documented in many drilling dates to around 600 BCE in west­ that is ~ide at the tip and constricted in regions of the world and represent a very ern India. Although we do not know the the midsection. This shape was developed efficient method of making a big hole with preCise form of the earliest diamond drills, '. by the Indus artisans to facilitate the the minimum amount ofeffort. Instead of·· they appear to ~ave included two different drilling oflong slender beads of hard stone drilling out the entire center ofa bead the styles. Some drills were made by using a such as carnelian,' agate and jasper. In con­ tubular dri.lJ: cuts a narrow and leaves single diamond chip that was crimped to trast to tapered drills, these hard stone drills the center of the bead a solid that can the end ~f a narrow bronze or iron drill are made from a specific raw material called be removed by a light tap once the tube shaft. Anther type ofdrill was made by «~rnestite," in honor ofErnest J.H.Mackay, has been cut through the entire bead.. crimping c,wo diamond chips at the tip who excavated the site of Chanhudaro, This technique ~as also used with tubular of the drill. The single diamond drilling Pakistan where a· carnelian bead workshop metal drills beginning in the early Bronze technique appears to have spread through- IJ.l with large quantities of drills and drill Age, circa 2500 BCE. out the northern and western parts ofAsia, ~ manufacturing waste was found. The earliest use ofhard gemstones for while the double diamond technique ~ f=: Microscopic examination of drilling drilling is difficult to determine since appears to have been practiced only in ~

striae on experimental and archaeological much of the early abrasives may have had' South Asia, primarily in the western bead l:O ~ stone beads and pendant making techniques Jonathan M. Kenoyer

producing region of Gujarat. all coarse particles. High quantities of or limonite Perforation of hard stone beads with Once stone beads could be produced will turn the rock a deep reddish orange

stone drills or abrasive is extremely time in larger quantities using diamond drills color which is called Itcarnelian", while ' consuming.. Experimental studies have the polishing of beads by hand was no smaller proportions of the, leave shown that chert or jasper drills can perfo­ longer economically viable and, we see , the agate apale yellow, called "citrine". ~ate agate at a rate of approximately 0.8 the introduction of'mass polishing tech­ with alternating bands of highly mm per hour. Ernestite drills are much niques. The earliest process was to place a porous and non-porous silica result in more effective at 2.4 mm per hour; and large number of beads in a watertight banded red and white agates that are the double diamoild drill can perforate at leather bag along with water and pow­ sometimes referred to as "sardonyx': If the rate of 536.5 mmper hour. Without dered agate or corundum. The precise the rock is heated in a reducing atmos­ , ,calculating the time involved in preparing mixture ofpolishing powder was kept phere with very little oxygen reaching the the beads and the drills, the introduction secret so that other people would not iron, it call turn grey or black, resulting of the diamond drill made it possible to be able to replicate the process. By rolling in blackand white banded agate 0 r drill beads at a rate 224 times faster than or shaking the bag back and forth for, onyX. Another way to' make a stone could be done with the most effective stone around 15 days, the beads would attain blacker is to soak it in a sugar solution or "or abrasive hand drilling techniques~ In a low luster polish. Bag polishing was' honey and then basically ~aramelize the fact, the introduction.ofdiamond drilling eventually replaced with mechanized sugar which has saturated the porous so changed the value of hard stone beads rumbling barrels using different grades of stone. This process has been documented, , such as carnelian and jasper, that elite abrasive and this is the technique used since the early Roman era and may consumers soon turned to beads made for most common shapes of beads have been practiced even earlier in 'from rolled or faceted gemstones such as today. However, specially produced long South Asia. There are several examples on flawless rock crystal, emerald, r~by and bicones, carved beads and faceted stone the Timeline of beautiful' agate beads diamond, as these were rare and more beads are all still polished by hand. with intentionally enhanced banding, difficult to manufacture. The color of some stone beads was particularly in Chapter 3., intentionally enhanced or modified by Many modern agate be~ds are colored Finishing various processes as early as 5000 BCE. with ~ wide range of chemicals to cre­ Since many beads are broken during Nodules containing agate and jasper may ate blue, green, yellow, reddish orange the drilling process, ancient beadmakers ,erode into massive gravel beds that are -and black colors. These processes were usually completed the final finishing then covered by other that not used in antiquity, and the modern, after the successful drilling of the bead. contain different types of minerals, dyed sto~es tend to be more uniform The finishing includes polishing, heat­ including iron, in the form of hematite ,in' color, without the luminosity of the ing or dyeing to enhance the color and or limonite. As ground water perco­ ancient examples. decoration using various techniques of lates through' the sediments it c:;trries ,Another technique for coloring stone surface modification. these iron minerals through the gravel is to bleach the surface to turn it white. Polishing a stone bead usually involves beds, 'which become saturated with fine This can be done most efficiently by repeated grinding with finer and finer particles of iron. Agate and jasper are dipping the'stone into an alkali solution abrasives to create a reflective surface. made tip ofmultiple layers ofsilica that or painting designs on the surface and Throughout most of human history the may have slightly different porosity due then heating the bead over' red hot polishing was done by hand, with initial to density of crystal formation, which, ' , charcoal. In ancient times the alkali polishing on fine quartzite or siltstone will affect the final appearance of the solution or "potash" appears to have

l.L\ " grinders, and final polishing on a wooden stone. Rocks with relatively uniform been made from a plant ashderived aZ or leather ,surface with extra fine abrasive porosity will turn a uniform color, from burning certain desert plants, and ::E powder. The abrasive powder can be made, depending on the amount and type of then mixed with natural plant resin to ~ ~ from finely ground agate or even brick dust ' iron found in the stone; as well asthe ,improve adhesion. The ash contains potassiu~ Ii: l:Q that has been carefully strained to remove degree to which it has been heated. and s'odium carbonate, and !: ' stone beads and pendant making techniques Jonathan M. Kenoyer

is still produced throughout West and South Asia, where it is used as a flux for melting glass and as well as for producing a form ofsoap. The whitening appears to be the result of tiny microscopic fractures in the stone surface as well as a bleaching ofany natural colors in the stone. Mter ,thousands of years the bleached surface often erodes, leaving a shallow etched design that led earlier scholars to refer to

these beads as being "etchedn. The term "etched carnelian" is still used in the liter­ ature to describe red carnelian beads that have white designs painted on their surface. from the Indus Valley have been found in Mesopotamia, most notably in the mid-3rd millennium BCE tombs at . Examples on the Timeline in ~hapter 7 are typical of FIGURE 4: Left-hand images show hand polished canelian beads, hand p0lishing with bow~turned beads from the Parthian and Sasanian wheel and other polished agate beads. Middle image of two men engaged in l~ther bag polish­ ing. Upper right is a wooden drum polisher, lower replication of bleached , with three periods, although decorated carnelian beads ancient bleached carnelian beads, often called etched carnelians. have been prodced into modern times. Beads that have a white surface and black beads and stamp seals, such as those in process described previously. lines appear to be the result of improper Chapter 1, were formed by this technique. Conclusion firing where the overall surface of the At times, the surface of the stone was Stone bead making is a fascinating topic bead was whitened from heating; the bleached using some form of alkali solu~ that still has many unanswered questions. painted lines became saturated with car­ tion. Large numbers ofsmall black and The creative abilitieS ofearly beadmakers bon, since they are more porous than white (often called "burnt," but probably and the continueq use of stone in manu­ the other surface areas. including some sort ofbleaching technique) facturing modern beads have resulted in Another technique of coloring was to steatite beads have been, found at ancient an almost unlimited combination of blacken the bead and decorate it with sites, and are shown on the Timeline techniques and raw materials. With the white lines. Several different techriiques , in Chapter 2. global trade ofbeads it is alniost impossible may have been used to achieve this Glazed steatite or quartz beads were to be certain ofwhere a bead comes from. effect, but the most common process ,made by coating the surface of the beads In the markets ofMrica, beads made in was probably to blacken the entire bead ' with finely ground silica colored with Europe, Asia and the New Worldcan'be l,1sing the carbonizing process described copper or azurite, and then heating under found next to locally produced stone beads. above and then to use the alkali tech­ controlled conditions. This very early The same situation exists in almost every nique to ,create the white lines. The pyrotechnology was particularly well corner of the world. It is only through famous TIbetan Zi (dZi) beads are made developed in Egypt as early as the last the careful study of all aspects of stone , with this technique. quarter of the 5th millennium BCE, and bead manufactur:e that archaeologists Soft 'talc or steatite beadswere usually predates Egyptian faience, glass, and glazed and bead collectors will be able to associate ~ heated to around 10000 C to harden the pottery. Some soapstone beads were specific beads to specific world regions :.}i::" talc by transforming it into another set of colored with' an iron pigment to turn and time periods. . ,"-' minerals called and enstatite, them. red, and red and white beads were and many ofthe earliest high-quality made using iron and the bleaching