Gemstone - Gemology and Jewelry books and Gem Identification A book of precious stones; the identification of gems and gem _(_PDFDrive_com_).pdf. A Book of. Precious Stones. THE IDENTIFICATION OF GEMS AND to the professional jeweller, a book of reference true that " gemology " may be included. book for GIA students, Shipley assigned Liddicoat the task books that can assist in honing your field gemology file/of/PDF/ofpamphlet. pdf).

Gemology Books Pdf

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We have thus compiled a simple “10 Steps to Gem Identification” free e-book for We hope that this free e-book is “Where Gemology Comes Alive” for you!. This is a digitalized library of non-copyrighted gemological books where you can download files format. If you are interested in studying gemstones from. Editorial Forum Book Reviews Gemological Abstracts. Gem News. ABOUT THE COVER: A wide variety of gemstones are now available for use in jewelry.

Nothing was done. I suggest that Mr. Duncan would be perfect to make this wonderful resource available to all who want to know. This central index could be manages by a group of interested experts and all the entries could be hot linked to the related articles or books that wanted to be part of this innovative project. Richand T. Liddicoat would be very proud From January-February through Winter , the A. The GIA again in the spring of became the publisher of the journal for the A. A and this is still true today.

As of the Summer issue the journal showed a large improvement because a new five-man editorial board was formed to oversee each article. The board positions were filled by the most eminent people in the subject of gemology and were changed periodically up to the present date.

Note change in scope and size with the April issue. Joseph O. Properly cared for. Nassau K. Stones that fade easily in light e. For example. Gems fi Gemology. Make-up which may cause discoloration. Frondel C. Paul Hamlyn. Consequently opals are best displayed in inside cases away from the case lights and direct sunlight. Jewelers' Circular-Keystone. New York.. Pearls should also be protected from damaging chemicals that might attack the nacre and from rough-textured fabrics that might abrade the nacre.

When one considers the history that accompanies gemstones. Opals are fragile stones. Allow the stone to cool thoroughly after boiling before any further work is done. The Medvedev approach to gem inlay. Winchester Press. Gems a Gemology. Koivula 1. Gems ei Gemology. Yale University Sinkankas J. Initially there was some question as to the identity of this material.

The polycrystalline character and often variable mineral content of manganoan sugilite results in a wide variety of material that might be considered gem quality. There it occurs in limited amounts as small brownish yellow grains in an aegirinc syenite host rock.

The attractive purple color is due to the presence of about wt. Dunn et al. John Pitlorino. The research reported here revealed that there are actually t w o types of gem materials that have heretofore been called sugilite: Ralph Coello provided material lor photography. Manganoan sugilite from the Wessels mine has been marketed under several trade names. Bank et al. W Fryer Examination of jewelry-quality siigilite shows that it consists o f manganese-bearing sugilite and other minerals i n a polycrystalline aggregate.

Within the trade. The mineral sugilite was first described by Muralzami et al. These two and the Wessels mine are the only known occurrences of sugilite. Clark et al. Forbes et al. Republic of South Africa. Its source is the Wcssels mine in the northern part of Cape Province. South Africa. Shigley John I. In contrast to single-crystal gem materials with gemological properties that generally fall within welldefined limits..

The authors thank Messrs. Elise Misiorowski. T h e material occurs in a large stratiform manganese orebody at the Wessels m i n e near Kuruman. Koivula is chiel gemologist. The appearance of the massive purple material from the Wessels mine bears no resemblance to the "type" material from Japan.

Shigley is director 01 research. Roger Dixon. Cecil Tuck. Eric Winterburn. The manganese is responsible for the distinctive purple color. Although standard gemological tests can indicate that both minerals are present in a single sample.

Using information from a recently published field study of the Wessels mine Dixon. This is followed by a gemological characterization of this material and of the chalcedony mixed with sug- Wesscls Mine Sugilitc ilite and a summary of the diagnostic features by which it can be identified.

The ring features a 6-ct ccibochon-cut center stone set in gold.

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This area of South Africa is part of the Kalahari Desert. The jewelry shown here combines fine siigilite in a variety of applications. Jewelry by Randy Polk. The bracelet illustrates various shades o f siigilite. Within this region. Although the correct varietal name for the sugilite from the Wessels mine is purple nunganoan sugilite. The necklace incorporates Most of the terrain is covered by sand. Annual rainfall averages 20 to 25 cm. Manganoan sugilite occurs in small quantities with other manganese minerals at the Wessels mine.

By the late s. With estimated reserves of eight billion tons of ore. Some of these deposits. In most places. The Wessels mine. Nature of the Manganese Deposit. This map of the Kuruman region shows the locations of the Wessels and other nearby manganese mines in the Kalahari manganese field. These deposits. Such stratiform manganese deposits are found in India. At the Wessels mine.

The manganese fields near Kuruman were 80 Wessels Mine Sugilite discovered early in this century see details in Boardman. Regional Geology of the Kalahari Manganese Field. Compared to the production of manganese. Dixon describes this group of minerals as forming a skarn within the layered manganese ore. The information presented below is taken from that article as well as from written communications with Dr. The siigilite occurs with black braunite and a light gray rock containing pectolite and possibly acmite.

The ore consists of braunite. Sugilite is found in massive form in layers or seams within certain zones in the manganese ore figure 3. The occurrence of Sugilite at the Wessels Mine. According to Sohnge The manganese ore occurs at several horizons within a sequence of sedimentary roclzs that is over Because of its minor economic importance relative to the manganese ore. The few reports published on sugilite since its discovery in lack specific information on the occurrence.

The regional geology of the area around the Wessels mine has been described by J. The thin layers in this sample are almost pure manganoan sugilite. Favorable conditions led to the deposition of various manganese minerals at certain layers in the sequence of sedimentary roclzs. When several sugilite layers occur together. The manganese was derived either from weathering of the surrounding land or from hydrothermal solutions that moved through the sediments during local episodes of volcanic activity.

The ore layers are quite rich. It is dark brown to black and occurs in massive layers. The sugilite is also found as irregular-shaped patches or as massive material that fills the spaces between brecciated blocks of manganese ore. Original minerals in the host rock are metasomatically replaced by new minerals.

In the original description. This representative sample 6 x 5 x 1 cm shows the layered appearance often seen in the material. A skarn is a mineralized ore deposit that results from the chemical interaction of circulating hydrothermal solutions with the sedimentary host rocks through which they pass.

The layers of sugilite mineralization are not continuous. Although not especially thiclz m. In the underground workings of the Wessels mine. No exact figures are available on the total reserves of sugilite at the Wessels mine. Photo by John Piiiorino. It was during our examination that we discovered that two types of material actually come from the Wessels mine: A miner working underground in the Wessels mine displays a chunk o f sugilite that has just been taken from the mine well.

Photo b y John Pittorino. At the mine. When sugilite is found figures 4 and Dixon [pers. He based this estimate on his field studies and on the occurrence and production of the sugilite mined thus far. Figure 4. Bird pers. Of the projected reserves. The original discovery resulted from an accidental encounter with a sugilite-rich area during normal mining operations. Narrow reddish brown veinlets up to 2 m m across cut through some samples in random directions.

Others with a relatively uniform color have an orbicular texture in which faint! Mn3 l2 lLi2Fe3 lSi. The luster on a brolzen surface is vitreous or resinous. In incandescent lightJ the material talzes on a more reddish appearance. Sanlples containing chalcedony that are lower in sugilite content retain the same purple hue but are less saturated ill color and are lighter in tone. A representative. Na] lNa. The most striking feature of the purer samples of sugilite is the purple color.

We found this material to differ in chemistry and i n absorption spectrum from the more common purple sugilite. There apparently is no relationship between the degree of transparency and the sugilite and chalcedony content.

Refractive Index. As described using GJqs color terminology the material generally has. Samples from the latter group exhibit gemological properties of both minerals! The properties of the samples composed of chalcedony mixed with sugilite are also reported in the text when they differ significantly from those of mangalloan sugilite.

Cleavage was not apparent in the samples we examined. The material varies from opaque to translucent. The specimens ore 2 cm hig Samples exhibiting the lower specific gravity of chalcedony 2. There is no way to iodide-benzyl benzoate solution of lznown 2.

As is common with other massive sanlz slowly in the liquid. The the random orientation of their nlicroscopic conremaining eight samples showed two separate stituents. To test for specific gravity we facet readings were talzen at various locations on selected six samples from the group of Sixteen of the 25 minerals found intermixed in some samples. The single testing procedures.. The samples examined are polydistinct reading of 1.

When the magnifying lens was removed from the refractometer! The sugilite samples sanlz readily of a particular sample by standard gemological in the liquid.

One of the faceted stones! This selection o f cabochons o f manganoan sugilile. The carving is 4 c m in diameter and wejghs 51 ct. Figure 7. In a sample of the chalcedony mixed with sugilite no narrow bands were observed. Absorption Spectra. Wessels Mine Sugilite Figure 8. The strength of these spectral features increases in intensity as the color of the sugilite becomes darker. Although this material was originally thought to be sugilite.

In addition broad regions of absorption below nm and from to nm were noted see spectrum illustrated in Fryer et al. It appears! When examined with a "handheld1' type of spectroscope and reflected lightl the sugilite samples were found to exhibit one or more of the following features: The narrow bands were much less obvious in the reddish purple color variety of sugilite but the broad absorption region from to nnl was still visible.

Photo b y Scott Briggs. The presence of sugilite ond other nlinerals in such o gronulor aggregate leads Lo the polymineralic nature of this material. The lorge peak centered at about n m corresponds 10 the brood region of absorption from to n m seen in the hand spectroscope. No directional variation in hardness was noted during testing. Witliin the visible region. The same remarks on color stability can be made for the samples containing both chalcedony and sugilite.

Those specimens that gave a 1. Other factors that appear to affect the hardness are texture and the thiclzness of the sugilite layers. The spectrophotometer absorplion curve of a polycrystolline sample of purple monganoon sugilite. These hardness values correspond to those reported by Dunn et al. The grains are approximately 0. In additionl none of the samples was found to have been treated with any color-enhancing dyes. Both sugilite and the chalcedony with sugilite are sufficiently durable for use in various jewelry applications.

They reported. It was noted. Ultraviolet Fluorescence. Most of the sugilite is cut in cabochon form figure 7. The chemical formilla of manganoan sugilite can be written as follows: Individuals who have worked wit11 this material report that good sanlples1 selected to be free of fractures and other defect!! When exposed to short-wave ultraviolet radiation1 six of the samples showed a slight reaction while the renlaining 19 were inert.

Tlie beoli is jasper m1c1 the legs ore Z gold. Chemical and X-ray Diffraction Data. Gemological Uses. Clarlz et al. Thusl such a fluorescence reaction seems lilzely to be due to the presence of chalcedony in the sample. Cl1einical coinposition data on nlanganoan sugilite have been publislled by Dun11 et al. All of the 25 samples were inert to long-wave nin ultraviolet radiation.

Plioto 0 fl 1r01d d Erica Von Pelt. The carving measures 52 x 35 x 7.

Photo b y Robert Weldon. Massive violet to purple dumortierite. Clockwise from the top. Whether dyed or naturally colored. Although the above-mentioned gem materials Figure The refractive indices of chalcedony and massive amethyst are so low in comparison to sugilite's 1. This material. Charoite is easily separated from sugilite on the basis of sight alone because of its distinctive interlocking. Los Angeles. Courtesy o f Sylvia and Ralph Coello. A cabochon of manganoan sugilite In many ways.

In contrast to the absorption spectrum of sugilite. The fact that sugilite does not fracture or cleave easily. This piece o f sugilite was carved i n a dragon motif by Hing Wa Lee.

As noted earlier. Olivier C..

Gems & Gemology - Jan. 1934 - Fall 2017 - 339 issues, 18,279 pages, 83 years of Gemology

We know of no sugilite that has been treated in any way to improve its appearance. Khan A. Fejer E. Belsky H. Wessels mine.. Pienaar H. Dixon R. Hurwit K. Dunn PJ. Schrader W Sogdianit -ein neues Edelsteinmineral? Miura V. Regional and Specific Deposits. These differ from the purer manganoan sugilite in their gemological properties. Kataeva Z. As a polycrystalline gem material. Gihwala D. Crowningshield R. Forbes W. South Africa: Some mineralogical aspects. Mineralogical Mquzine. Econonlic Geology.

Canadian Mineralogist. Springer Verlag. Geological Survey of South Africa.. We do not know how much of this latter material may appear in the market. Cape Province. Journal of Radioanalytical Chemistry. Din VK. Economic Geology. Annals of the Geological Survey of South Africa.

Gems e Gemology. Gems Q Gemology. Banerjee A. Dunn P. Shigley J. Wessels Mine Sugilite heat in normal wearing conditions.

Minerals Science a n d Engineering. Fryer C. Sohnge l? Geological Survey of South Africa. Kalahari manganese field. In virtually all cases. Hutchinson C. Elliott J. Briimmer J. Roy S. Transactions of the Geological Society of South Africa. Dusmatov VD. Pineda C. Frankel J.. Part 4. Northern Cape Province.

Klemm and H-J. American Mineralogist. Peisach M. Schneider W. Baur WH.

Dictionary of Gems and Gemology

With a hardness of 5'12 to 6' Boardman L. Pense J. Clark A. Zeitschrift der Deutschen Gemmologischen Gesellschaft.. Murakami N. Bank H. Dillman R. Kato T. Mineralogical Journal lapan. Khoroshilova L. Sugilite can be readily separated from similar-appearing materials. Efimov A. Bearne C. Koivula J. Sugilite is also color stable to both light and.

Handbook of Strata-bound and Stratiform Ore Deposits. Handbook No.. Couper A. Hirowatari F. Part Memoir No.

Button A. Mineralogical Record. Wilson WE.. The following grades were assigned to these three round brilliants: Fancy purplish red 0. This extraordinary sale set a new world record per-carat price. According to Mr. The three fancy-color diamonds figure I were put up for auction by the heirs of a Montana collector. Kane Three fancy-color diamonds were recently sold at auction b y Christie's.

For the few descriptions in the literature of such stones. These stones were assembled by a Brazilian cutter from rough downloadd at various mines in Brazil. This article provides a comprehensive description o f the visual appearance and gemologiccil properties o f these three diamonds. Also sold at the recent auction were a I11 August Fancy purple-pink 0. These diamonds are notable for their unusual colors. April The purpose of this article is to document the gemological characteristics of these three extremely rare fancy-color diamonds see table 1.

May Rarest of all is pure red with no secondary hue. Christie's also gave the laboratory and the GIA Research Department the opportunity to study and photograph them. All three diamonds showed almost total absorption below nm. This absorption became extremely intense when the diamond was cooled. Shepherd Courtesy of Christie's. In the almost 30 years of records of Gem Trade Laboratory reports available.

Kunz and These three round brilliants are among the rarest of fancy-color diamonds. At room temperature. Ball and Gaal The 0. They arc. No Unlike the If the luminescence is strong enough. TABLE 1. The absorption spectrum of the 0. The gemological properties of three notable fancy-color diamonds Properties Color Absorption spectruma nrn Transmission luminescence Long-wave U. Transmission luminescence was readily visible in the 0.

Such a pattern is frequently referred to as the "tataini" type of birefringence pattern because of its resemblance to the Japanese woven mat of that name Orlov. The mottled birefringence areas are irregular patterns that appear to undulate as the diamond is moved within the field of view. All three diamonds -from left t o right here. When this last diamond was positioned table-down toward the edges of the concentrated beam of illumination. The three diamonds reacted essentially the same to shortwave U.

Cross-hatching of the linear bonded strain patterns forms a "tatami" pattern. V radiation. The strong linear banded strain patterns intersected in two directions in some areas to form a cross-hatched pattern.

When exposed to long-wave U. Photo b y Shane McClure.

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When exposed to X-rays for a few seconds. Also present throughout this diamond were strong mottled and localized strain patterns.

Although the specific causes of color in diamonds in this color range are not entirely understood. Considered in conjunction with the author's experience with numerous pink and purple diamonds of somewhat low tonal values much lighter in color than the diamonds discussed here.

Figure 6. The two directions of color graining were also present in the 0. In the 0. The "tatami" pattern was also easily visible as color graining in the 0. This is readily apparent through the microscope as graining and color zonations within the graining which can vary from weak to quite prominent. In these two diamonds. The three diamonds examined in this study exhibit closely spaced red and pink graining and color zoning see figure 7. Diffused light. The closely spaced red and pink graining and color zoning seen in the 0.

Gaal R. The Mineral Industry. Figure 8. Notes and New Techniques Kunz G. Darkfield illumination. The two smaller diamonds were found to contain naturals. Gemsel Gemology.

Orlov Y. Magnified 25 X. A second cavity-long. Gcmological Institute of America. Gemological Institute of America. A deep cavity i s evident in t h e table of the 0.

A second cavity i n t h e 0.

The O. Note the frosted appearance in reflected oblique illumination. There are three naturals: Kanc R. Corns e Gemology. Hofer S. It is interesting to note that the highly irregular surface of this second cavity was transparent and glossy in darkfield illumination. The slightly iridescent fracture seen extending inward from the girdle is aligned precisely with one of the tightly spaced graining planes easily visible through the pavilion. Shepherd G. W h e n viewed from the pavilion.

Kunz G. This strong absorption has been identified as being associated with water Wood and Nassau. Unpolarized spectra were acquired in the range cin. X-ray fluorescence that involve equipment that is generally too expensive for practical ownership by most gemologists can then be applied as a last resort.

The technique is nondestructive and. Troup and Hutton. The synthetics also include those in the previous study and samples from Russia bothflux and hydrothermal. By contrast. Origin and number of samples of natural and synthetic emeralds tested by Fourier transform infrared spectroscopy. Fourier transform infrared FTIR spectrometry. The natural emeralds came from a variety of localities: Laboratory methods e. It is especially useful for identifying stones that contain n o distinguishing inclusions.

Although inclusions usually enable gemologists to distinguish natural from synthetic emeralds. More than one of these has proved useful in separating synthetic from natural emeralds Griffiths and Nassau. Various manufacturers continue to produce and introduce synthetic emeralds figure 1.

Stockton Infrared spectroscopy provides a means t o distinguish natural from synthetic emeralds i n the range cm. The most obvious difference is the absence in the flux stones of the strong absorption between and c m l. As mentioned above. Most of the absorption features seen in this range for synthetics were also seen to some degree in natural emeralds. Haupt at Swarovslzi in Austria. Among the more recent synthetic emeralds introduced are the Biron hydrothermal top. One is a product that was grown experimentally between and by Dr.

The infrared spectra of natural and hydrothermal synthetic emeralds are more similar to one another. No Notes and New Techniques interpretation of these features has been published. The other is the Russian hydrothermal product. The Russian and Swarovski synthetics g. A representative sample of infrared spectra for t w o natural emeralds a and b. Features that can be used to distinguish natural emeralds from hydrothermal synthetics are labeled on spectra a and b.

T h e flux synthetic emerald spectra c and d clearly lack the strong absorption at about c m. T h e spectra of hydrotherm a l synthetic emeralds e-i illustrated here also exhibit features labeled that can be used t o distinguish these synthetics from natural emeralds. I that is evident i n the spectra of all the natural and hydrothermal synthetic emeralds.

Features in the cm-1 range can also be used to distinguish these troublesome hydrothermals from natural emeralds. It is. In the synthetics. Wood and Nassau. The results of this study suggest that infrared spectroscopy provides additional means to distinguish natural from synthetic emeralds.

With a Fourier transform instrument. The cm-I band was never observed in the synthetics. All four of these specimens showed spectra that are deceptively similar to those of natural emeralds figure 2. Journal of Cemmology.. The latter show at least two and. All three Russian stones have two of the features mentioned above.

While none of the diagnostic features completely disappeared at any orientation tested. Schrader H. Smaragden und Alexandriten. Wood D. Griffiths J. In the Swarovslzi specimen.

Applied Spectroscopy. Journal of Gemmology. Stockton C. Hutton D. Troup G. As a result. Acicular needle-like crystals and crystal groups of brownish yellow to red rutile are relatively common as inclusions in both rock crystal and smoky quartz.

It was also observed that wherever these inclusions reached the surface. Not one of these inclusions was found to be contained completely within the topaz. All photomicrographs were taken by the author. Most of the gems are colorless. West Germany. Because they are so similar in appearance to rutilated quartz. Brazil G. The author would like to thank Mr. Undoubtedly the latter stones have been irradiated and heated.

Teofilo Otoni. Gerhard Becker of Friedr. August Becker in Idar-Oberstein. During this investigation. Because the inclusions were too small for X-ray powder diffraction to be performed and because there was no means of chemical analysis available such as an electron microprobe. They are faceted. Emmanuel Fritsch. Over the past two years. This finding suggested that the body color of the inclusions might have been derived from an outside source and was not necessarily inherent to the true nature of the inclusions themselves.

The first of these features was a general observation that. Rutile is not known to crystallize in topaz in a ribbon-like habit that would produce such a directionally dependent effect.

When viewed in an edge-on direction. Decker and D.

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When one of these topazes is examined with the naked eye. These are not the types of surface markings that one expects when slightly softer solid inclusions such as rutile.

The polishing-wheel action causes the spallingoff of tiny chips from the rim of the fracture which are then pulled along by the wheel. Photo Tino Hammid. This latter phenomenon. The inclusions are so ribbon thin that m a n y o f them are barely visible in this pavilion view o f the stone shown in figure I.

Incomplete filling of the inclusions provided additional proof that they are not rutile. This scores the surface of the material being polished and produces the visual evidence we see in figure 4.

They are much deeper and are reminiscent of the drag lines observed when preexisting fractures of similar surface-reaching hollows are polished over perpendicular to their length. These inclusions in topaz could easily be mistaken for rutile.

Photo 63 Tino Hammid. Table-up view o f this Darkfield and oblique illumination. Acicular rutile inclusions are single crystals and as such would not contain randomly spaced gaps at uneven intervals down their length. This dense. The incomplete filling of the inclusions provides further proof that they are not rutile.

These polishing drag lines on the surface of a topaz extend from the ends of the "inelusions. When oblique illumination was used.

No double refraction was observed. As a final test. Oblique illu minution. Thin-film iridescence from some of the unstained areas along. Oblique illumination. This provided additional proof of uneven channel filling. Once trapped. This epigenetic iron staining. This resulted in the formation of many dislocations leading away from the solid inclusions. CA Or call To order one or both sets. Natural etching along these dislocations followed or could have occurred continuously as the host topaz was growing.

Horney R. Mineralogical Society of America. Referring back to figures 1 and 2 will show how important proper lapidary orientation is with this material.

Fluid lncliisions. Actu Crystullogruphicu. Observations and illustrations of similar inclusions in topaz by Dr. A limited number of back issues for earlier volumes are also available.

The lapidary must orient the rough so that the inclusions will appear boldest to the eye when the finished faceted gem is in the table-up position. A great deal of care must be taken during the faceting of these topazes because of the directional nature of the inclusions.

All of the above-noted observations. Please write or call the Back Issues Department for information on the availability of specific issues. Edwin Roedder strongly support this characterization compare the photomicrograph on page 25 of his book with figure 7 here. Please allow weeks after payment for shipments i n the U. Rocdder E. All payments must be in U. The final step was epigenetik. Such dislocations are a known invitation to etching Phalzey and Homey.

Because the overall color was so dark. These straight and curved out of focus i n c h sions were determined t o be tremolite needles i n epidote. New York Karin N.

The stone resembled deep green tourmaline in appearance.Only alexandrite exhibits a weak, red luminescence under SWUV light. A vitreous variety of Persian turquoise from Nishapur, Iran. Although the correct varietal name for the sugilite from the Wessels mine is purple nunganoan sugilite. If you are interested in studying gemstones from both scientific and historical perspectives, this is a treasure trove of knowledge that will literally take years to finish reading.

Because the metal for a tube setting is usually thicker than that of a bezel. Kato T.

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