gems, beryl, emerald, Libya, history of emerald, North Africa

Discusses the “Libyan” emeralds of the ancient world. Monod critically examines the tradition of the supposed “Emerald of the Garamantes,” associated with the ancient Garamantes of the central Sahara. Drawing on classical texts and later interpretations, he traces the development of the story and questions the identification of the material described in ancient sources as true emerald. The study considers the geographical, historical, and mineralogical evidence behind the tradition and illustrates the difficulties created by applying modern gemstone names to ancient terminology. Monod concludes that the celebrated “emerald” tradition cannot be accepted straightforwardly as evidence for an ancient Libyan source of true emerald.

inclusions, gems

Uses practical examination stones to demonstrate how systematic microscopy and absorption spectroscopy can guide rapid gemstone identification. Drawing on twenty years of supervising Gemmological Association examinations in Lucerne, Gübelin argues that practical experience and an organised testing strategy are more valuable than memorised constants alone. He describes identifying ten unrestricted-test specimens from the June 1973 diploma examination within approximately half an hour, beginning with magnified inspection and selecting confirmatory tests according to the features observed. A green stone is identified as synthetic emerald from a characteristic wispy inclusion pattern and a phenakite crystal, supported by dichroism and immersion observations. A translucent green cabochon is assigned to fei cui through an absorption line at approximately 437 nm, a refractive-index reading near 1.66 and density behaviour in methylene iodide. Two- and three-phase fluid inclusions with weak relief, irregular outlines and halite daughter crystals suggest fluorite in a pale yellow stone; optical isotropy and a refractive index of 1.44 confirm the identification. Spherical bubbles at a junction, contrasting internal features and immersion reveal a red almandine–glass doublet. Hair-like fluid channels, or trichites, indicate tourmaline in a triangular crystal slice, with immersion and conoscopic observations providing additional support. Strong doubling of pavilion facets and a prominent absorption line near 653.5 nm identify zircon. Angular growth zoning, dichroism and absorption in the blue region support identification of a natural blue sapphire. Rutile needles, absorption spectra and refractive-index measurements distinguish rhodolite and almandine garnets. The most difficult specimen, an inclusion-free pale yellow stone, is recognised as apatite through faint absorption lines attributed to didymium and confirmed by refractive indices of 1.640 and 1.644. Photomicrographs illustrate the internal structures used in these determinations, including synthetic emerald feathers, fluorite fluid inclusions, tourmaline trichites, sapphire zoning and garnet silk. The article advocates an adaptable sequence of observation, interpretation and targeted confirmation, encouraging students to develop familiarity with diagnostic features through repeated practice. Its central lesson is that effective use of the microscope and spectroscope can reduce unnecessary testing and improve confidence and efficiency in practical gemmology.

corundum, Tanzania.12, gems

Bank describes an unusual mineral assemblage from the Lake Manyara area of Tanzania in which emerald, alexandrite, and ruby occur as components of the same paragenesis. The brief report records the association of three important gem varieties—chromium-bearing beryl, chrysoberyl, and corundum—and discusses their occurrence and mineralogical relationships within the deposit. The association is noteworthy because minerals of three different gem species, all capable of deriving their characteristic colors from chromium, occur together in a single geological environment.

jade, jadeite, fei cui, nephrite, glass, imitations, simulants, gems

Crowningshield reports several glass gemstone imitations examined at GIA’s New York laboratory, emphasizing how convincing colour, internal crystallization, and manufactured structures can complicate identification. A group of green jade substitutes submitted within a few weeks ranged from ordinary translucent glass to partly devitrified material closely resembling fine fei cui. One relatively straightforward imitation was mounted in platinum with diamonds, illustrating that an elaborate setting does not establish the identity of its principal stone. Another fine green example showed an unusual radiating fibrous pattern. Crowningshield relates such crystalline or partly crystalline structures in glass to devitrification and compares them with the fern-leaf appearance of the Japanese imitation sold as meta-jade or Iimori stone. In that ring, the apparent surrounding diamonds and their prongs were simulated by cutting the metal setting itself. A further 31 ct cabochon resembled valuable imperial fei cui but contained irregular crystal-like structures or tufts produced by devitrification. Another imitation was identifiable as glass from prominent gas bubbles, although its refractive index of 1.66 and mottled appearance so closely approached those of fei cui that two trade members wagered on the laboratory’s conclusion. These cases demonstrate that apparently mineral-like inclusions and plausible optical measurements must be considered alongside decisive microscopic evidence. Other glass substitutions included a bracelet purchased as natural emerald crystals, whose components were manufactured hexagonal prisms, mostly green and sometimes incorporating a brown imitation matrix. The report also describes attempts to reproduce cat’s-eye phenomena in glass. An early white product contained visible hollow tubes that scattered light and generated chatoyancy, while later imitations were available in several colours, including honey-like shades and pale blue. Some displayed sharp eyes despite structures too fine to resolve readily at ordinary gemmological magnification. Side views revealed honeycomb patterns, initially attributed tentatively to devitrification. A brownish yellow example resembling chrysoberyl showed a pronounced fibre-optic effect and larger hexagonal areas composed of numerous smaller hexagonal fibres. Its precise manufacturing method remained uncertain, although fused optical fibres were suggested; its refractive index exceeded the instrument’s scale and its specific gravity was 4.19. Photographs document the internal textures and viewing effects. Collectively, the observations show the variety of glass substitutes and the importance of examining structural details from several directions rather than relying on colour, apparent inclusions, jewellery quality, or a single test.

corundum, India.12, ruby, sapphire, history.1, gems, Indian lapidary

Sinkankas: Gemstones as viewed by an Indian author steeped in traditional lore presents a perspective deeply rooted in India’s enduring cultural relationship with gems, much of which remains seriously regarded today. As noted in a review in Gems & Gemology (Vol. 14, No. 2, 1972, pp. 61–63), the work is a unique combination of Indian culture and gemology." The lengthy and valuable introduction offers insights into Indian gem lore, tracing its origins to ancient texts as well as to more recent sources, many of which are cited by the author, Tank, along with the names of their authors. Topics discussed include the critical importance of imperfections in gems, distinctions between synthetics and naturals, and traditional Indian classifications, listing 84 gemstones in total. At the heart of the book is a focus on the nine traditional gems—emerald, diamond, pearl, coral, zircon, blue sapphire, sapphire, ruby, and cat’s-eye—shown on the color plate preceding the text. These are described using both traditional beliefs and modern scientific knowledge, with an emphasis on the qualities a gem must possess to be considered protective or influential. Tank also explores various gem varieties, their sources, and recommendations for when and where they should be worn for their protective powers. For instance, in the case of pearls, shape is crucial, and over 20 forms are illustrated with their Indian names. The book also includes synonyms for gems in different Indian languages and covers additional stones such as garnet, feldspar, quartz, opal, topaz, tourmaline, and beryl. It concludes with short notes on lapidary treatments and birthstones. Monochrome plates primarily depict cutting styles and one plate on inclusions. Unfortunately, and typically of much modern bookbinding in India, the physical binding is very poor—the spine is unrounded and the inner hinges tend to break upon opening. As noted in Rev/Gemm (Vol. 13, No. 6, 1973, p. 239), the book is not a scientific treatise."

gems, geology, East Africa, Kenya, Tanzania, Mozambique belt, Gondwanaland

Gemstones in Gondwanaland. Gemstone localities throughout the world were studied and all districts producing more than two gem species were listed. Van Nostrand’s Standard Catalogue of Gems was consulted extensively. Excluded from consideration were: 1) diamonds; 2) gems such as opal and dioptase which can form in many geological environments via rising or descending waters; 3) gems worth less than $1 per carat; and 4) gems from one-of-a-kind localities such as Franklin, New Jersey. Emerald and amethyst had to be treated as special cases. Seventeen districts qualified for the listing, and of these, 13 were found to lie in an apparently mappable belt running across Gondwanaland. Gem mineralization in all 13 cases appears to be circa 550 million years, although some dates were obtained by inference. Other striking geological similarities were also noted. Some tentative gem correlations between East Africa and Madagascar were made based on the fine structure of the gem belt, leading to a proposed pre-drift position for Madagascar farther north than usually shown. Three of the four remaining gem districts—New York/New England, California, and Carolinas/Virginia—differ in character from the Gondwanaland belt districts and from one another. The fourth, the Urals, seems similar to the Gondwanaland belt but more data is required. Other USSR districts may exist.

corundum, synthetic corundum.7, gems

Webster surveys synthetic crystalline materials developed since 1946 that have entered the gemstone trade or offer potential for ornamental use, bringing together scattered literature and results from his own examinations. Arranged alphabetically by chemical or species name, the review includes synthetic equivalents of natural minerals and manufactured compounds without known natural counterparts. Established pre-war Verneuil corundum and spinel receive only limited attention, while crystal-growth methods are outlined rather than discussed in detail. Identification is approached through physical and optical constants, internal features, absorption spectra, fluorescence and phosphorescence, X-ray transparency, electrical conductivity and, where relevant, magnetism. Particular attention is given to synthetic emeralds from Chatham, Gilson, Zerfass and Linde, together with Lechleitner’s synthetic-emerald-coated beryl and layered constructions. Earlier synthetic emeralds commonly differed from natural stones in refractive indices, birefringence and density and showed characteristic veil-like inclusions and strong luminescence. More recent products increasingly overlap natural emeralds in their measurable properties; the addition of iron can suppress luminescence, making careful examination of inclusions especially important. Flux-grown and hydrothermal rubies likewise present greater identification difficulties than conventional flame-fusion material, with seed remnants, feathers, distinctive inclusion patterns and radiation responses providing possible evidence of synthesis. The diamond section records the progression from commercially useful industrial crystals to General Electric’s May 1970 announcement of gem-quality synthetic diamonds of approximately one carat or more, while noting that production costs still exceeded those of comparable mined stones. Extensive coverage is also given to garnet-structured compounds, particularly yttrium aluminium garnet, and to diamond simulants including strontium titanate, rutile and lithium niobate. Their usefulness and detection are considered in relation to dispersion, birefringence, density, hardness, colour and durability. Other entries discuss coloured synthetic quartz, fluorite, scheelite, periclase, silicon carbide, zincite, zircon and several less familiar or experimental materials. Developments in spinel include red flame-fusion stones, flux-grown crystal groups used uncut in jewellery, sintered material imitating lapis lazuli and material displaying a moonstone effect. Throughout, trace-element additions are shown to influence colour, spectra and luminescence, so that specimens of the same nominal material may behave differently. Photomicrographs, spectral diagrams, a comparative radiograph, tables of constants and a selected bibliography support the descriptions. The compilation distinguishes established commercial products from experimental or merely prospective gemstones and provides a contemporary reference for the increasingly varied identification problems posed by synthetic crystals.

corundum, ruby, sapphire, quality.10, gems

O’Donoghue documents prices paid by the Reverend Chauncy Hare Townshend for gemstones acquired from the celebrated collection of Henry Philip Hope, using manuscript annotations in a museum copy of B. Hertz’s 1839 catalogue of that collection. These annotations provide a rare record of prices paid for good-quality gemstones during the middle nineteenth century. Townshend subsequently bequeathed his collection of precious stones, together with pictures, drawings and watercolours, to the institution then known as the South Kensington Museum, later the Victoria and Albert Museum. Although the Townshend Collection contains 154 items, the article is restricted to stones purchased from the Hope sales. The entries link descriptions and purchase prices with references to Hertz’s catalogue and museum accession numbers, recording dimensions and, where available, historical weights. Because the collection was sealed in a security case, the author could reproduce only some of the weights quoted by Hertz. The gemstones are mounted in gold rings, some constructed to swivel so that their backs can be examined. The catalogue covers diamonds, sapphire and other corundum, topaz, tourmaline, garnet, peridot, emerald, aquamarine, opal, quartz varieties and turquoise. Recorded prices include £250 for a lemon-yellow diamond, £85 for a green diamond and £30 for a small diamond described by Hertz as approaching red spinel in colour. A deep claret-coloured topaz cost £180, compared with £25 for a yellow topaz showing reddish ends. Aquamarines range from £15 to £300, while the listed opals range from £4 to £70. Descriptions preserve distinctive features such as chatoyancy, iridescence associated with fractures, colour variation, dendritic inclusions and engraved decoration. Examples include an emerald engraved with Persian characters, a garnet engraved with a faun and turquoise carved with a female head in relief. The article also corrects several earlier identifications: stones catalogued by Hertz as zircon are identified as tourmaline, hessonite and aquamarine, while two specimens listed as ruby spinel are assigned to corundum. By connecting surviving museum objects with their earlier catalogue descriptions and documented purchase prices, the paper supplies primary historical evidence for the study of nineteenth-century gemstone collecting and valuation.

gems, beryl, emerald, Brazil, Colombia, China, Zimbabwe, Pakistan, Zambia, Madagascar, Mozambique, inclusions

Sinkankas: Very handsome, imaginatively designed book, with the unusual feature of the title being spread over three pages. Apparently this work was meant to be the first of a series of monographs on gemstone families but up to date (1988) no others have appeared. The first part treats emerald history, in the East, as known to Pliny, origin of the name, curious lore surrounding, famous emeralds, and the color and causes. The second part describes world emerald deposits with most space naturally devoted to the Colombian mines, type crystals, and a discussion of trapiche crystals. The third part provides property data, considerable detail on inclusions in emerald, doublets & imitations, and the methods of gemological investigation . Next appear four tables of constants of natural & synthetic emeralds, comparisons of emerald to other similarly-colored stones or imitations, and fluorescence of emeralds from various deposits. The bibliography, unfortunately, is replete with errors in contrast to the text which is relatively free of defects. The mostly high quality illustrations show natural specimens, minerals that could be mistaken for emerald, cut stones, a Russian postage stamp depicting Siberian emerald, jewelry set with emeralds, absorption spectra, and many photographs of inclusions but these last lack the quality of the other illustrations. Rev R K Mitchell, J Gemm, 11, 7, 1969, 272–3, notes errors in biblio & elsewhere.

gems, jewelry, ancient jewelry, Greek, Etruscan, Roman, gold, history of jewelry, history of rings, glyptic, engraved gems, collection, comaranda, catalog

Modern jewelry is prized for its pearls and precious stones—for the fine cutting of the stones and for their elaborate setting; this was not the case in antiquity, when diamonds and rubies were virtually unknown, and when emeralds and sapphires were extremely rare, and the pearls and the precious and semiprecious stones that were sparingly used in Hellenistic and Roman jewelry were usually left rough or, if cut, cut cabochon—that is, in a smooth rounded form; ancient jewelry was treasured for its gold and, to a much lesser extent, its silver, for gold had been valued since remote antiquity on account of its rarity and incorruptibility, and the survival of Greek and Roman gold coins and gold jewelry, as well as the reports of gold vessels and statues once deposited in ancient treasuries but now lost, reveal the value placed on this metal and the special uses to which it was put, whereas silver, though far more common than gold, corrodes, and the vast numbers of ancient silver coins and vessels that we have today owe their survival to their relatively substantial form, since delicate jewelry of that metal cannot be expected to have survived in quantity—and indeed, little has—but the real reason may be that little was made, as tarnishing would soon render it unsightly, and when in contact with skin for repeated periods, silver can cause infection, so the ancients surely discovered, for instance, that silver earrings were not suitable for pierced ears.