gems, jade, fei cui, pyroxene jade, jadeite, fei cui, omphacite, kosmochlor, ureyite

The new mineral NaCrSi₂O₆ (ureyite) has been found as rare emerald green grains in the iron meteorites Coahuila, Toluca, and Hex River Mountains. X-ray studies of both the natural and synthetic material have established that the mineral is isostructural with jadeite, NaAlSi₂O₆. Indexed data for powder patterns obtained by X-ray diffraction and precise cell dimensions are given for the Cr, Fe, and Al members of the jadeite group. Unlike jadeite, a high-pressure phase, ureyite can be synthesized from melts at 1-atmosphere pressure.

Gilson, Chatham, Zerfass, Farben, gems

gems, Brazil, emerald, topaz, quartz

Review of the gem deposits of Brazil.

beryl, emerald, Rhodesia, Sandawana, Zimbabwe, gems

E.J. Gübelin characterizes emeralds from the recently discovered Sandawana deposits in Southern Rhodesia [Zimbabwe], combining an account of their discovery and geological setting with chemical, optical, and microscopic examination intended to establish distinguishing features of origin. Prospectors Laurence Gontat and Cornelius Oosthuizen found the first emeralds in October 1956, followed seven months later by a richer occurrence. The deposits lie on the southern side of the Mweza Range, where pegmatite dykes intersect tremolite schists within a complex assemblage of ancient metamorphic and intrusive rocks. Gübelin interprets emerald formation as a product of contact metamorphism bringing beryllium-bearing granitic material into interaction with chromium-bearing rocks derived from ultrabasic intrusions. Study of ninety-two cut stones reveals a vivid emerald-green colour with a yellow glint, retained even in very small gems. Fracturing and small crystal size limit most available cut stones to less than a quarter carat. Chemical and spectrographic analyses indicate appreciable magnesium and sodium, together with chromium, iron, and lithium, although the small amount of material available restricts analytical accuracy. Detailed physical measurements on ten selected stones establish comparatively high refractive indices, with representative values near 1.593 and 1.586 and birefringence of approximately 0.007. Specific gravity is likewise relatively high, averaging about 2.756. The emeralds show yellow-green and bluish-green dichroism, a weak red response through the Chelsea filter, and the usual chromium-related absorption features. They are inert under both long- and short-wave ultraviolet illumination but display pale-red fluorescence in a crossed-filter fluoroscope; ultraviolet transmission ends sharply near 320 nm. Gübelin emphasizes that overlap in physical constants among emerald sources makes these measurements insufficient for reliable provenance determination by themselves. Internal characteristics provide stronger evidence, particularly short tremolite pins and exceptionally fine, sometimes curved fibres occurring singly or in bundles. Their morphology and distribution are compared with amphibole inclusions in Habachtal emeralds. Additional features include partly resorbed garnets with brownish halos, limonite-filled cracks, rare hematite, feldspar and magnetite inclusions, dustlike patches, and distinctive systems of fine fissures parallel to the basal plane. Lace-like residual liquid films observed in one stone are recorded without being treated as an established locality characteristic. Photomicrographs and comparative tables support the conclusion that Sandawana emeralds combine attractive colour with a recognizable suite of internal features useful in distinguishing them from other contemporary sources.

gems, emerald, beryl, synthetic emerald, hydrothermal synthesis, crystal growth

First report of beryl synthesis using hydrothermal growth method.

corundum, history.1, gems, jade, Fischer-Other, early lapidaries

According to Caley and Richards (ibid., 4), the treatise is a set of notes, possibly taken down by a student listening to lectures delivered by Theophrastus, but “safely assumed to represent the actual views of Theophrastus, and he may reasonably be considered the author.” On the other hand, Eichholz (ibid.) is firmly of the view that the treatise is Theophrastus himself, and that it is not a fragment, as has been suggested numerous times, but a complete, though short, work. Theophrastus’ treatise, commonly called the Peri Lithon, or “Concerning Stones,” commences with speculations as to the origins of stones and discusses their distinctive properties as well as the means by which differences among them may be elucidated. This is followed by a rather rambling description of numerous gemstones and earths, excepting metallic minerals and metals, which are stated to have been described elsewhere in a treatise now lost. All of the matter is presented tersely and is almost entirely free of superstitious lore, except for the emerald, for which it claims that it refreshes the eyesight upon gazing and that an emerald placed in water colors it green. F. D. Adams (Birth and Development of Geological Sciences, 1938, 19) notes that “it differs entirely in its style and content from any other work upon this subject written in classical times—in fact, no other work at all resembling it appeared until later on in the Middle Ages. It remained for 1800 years a most valuable and authoritative work on minerals, referred to and quoted by all, and shows that even at this early time there existed, probably among miners, quarrymen and other men engaged in the technical trades and industries, a body of knowledge of mineralogy, especially on its practical side, which had been drawn upon by Theophrastus in the compilation of his work.” Adams further notes that Pliny must have had a more complete version of the treatise because of mentions of stones that are not now in the Peri Lithon, but this is refuted by Eichholz as noted above. H. Tertsch (Das Geheimnis der Kristallwelt, 1947, 31–4) also provides illuminating remarks on the treatise, suggesting that it reflects the views of Aristotle, his mentor. The gemstone content of Peri Lithon is not large but important for those ornamental and precious materials that it does name—namely, marbles and calcite onyx, lapis lazuli, obsidian, and other massives, and also emerald, sard, garnet, adamas (probably corundum), amber, rock crystal, and others—all of which are carefully examined by Caley & Richards and by Eichholz, who make identifications where possible. Both authorities offer much ancillary material which makes rewarding reading as well as providing lists of printed editions of Peri Lithon from which I have freely drawn much of the information below on not personally examined.

gems, pearls, precious stones, jewelry

Hatem presents a popular but substantial survey of pearls and precious stones, combining gemological information with history, geography, mining, trade, and famous gems. She discusses the principal gemstones, including diamond, ruby, sapphire, emerald, and pearl, describing their formation, physical characteristics, important producing regions, methods of recovery and cutting, and their place in commerce and jewelry. Historical accounts and anecdotes trace the fascination with precious stones from antiquity to the modern period, including celebrated jewels, royal treasures, discoveries, and the development of major gem-producing districts. Synthetic gemstones and attempts to manufacture diamond are also treated, including Moissan’s experiments. Pearls receive extensive attention, with discussion of natural pearl fisheries, cultured pearls, mollusks, formation, grading, and important producing regions. Written for the general reader rather than as a technical gemological manual, the volume brings together scientific explanations and historical material and is extensively illustrated, with 78 figures and a map in the text and 103 illustrations on plates.

beryl, emerald, Austria, gems

Gübelin investigates whether emeralds from Habachtal, Austria, possess characteristics that distinguish them from emeralds of other origins, combining a review of mining history and geology with measurements and detailed microscopic examination. He recounts the deposit’s reported exploitation from antiquity onward and the repeated difficulties encountered by later mining ventures. Its position at approximately 2,100 metres in the Hohe Tauern, hazardous access, prolonged winters, modest production, and short mining licences are presented as obstacles to sustained commercial development. The emerald-bearing zone lies near the contact between central gneiss and surrounding schists. Gübelin interprets its formation through contact metamorphism and the interaction of granitic residual solutions with neighbouring rocks, assigning the beryllium supply to granite and the chromium responsible for green colour to serpentinite. Biotite schist is the principal host, accompanied by tremolite, actinolite, chlorite, and talc-rich rocks; he draws parallels with emerald deposits in the Urals, India, and the Transvaal. Most local beryl is pale or greyish green, while only a small proportion displays fine emerald colour, and abundant inclusions commonly diminish transparency and value. Crystals generally show simple prismatic forms, sometimes flattened according to their orientation within the schist. Measurements on eleven specimens establish average refractive indices of approximately 1.591 and 1.584, birefringence near 0.007, and an average specific gravity of 2.74. Dichroism is generally weak, combining yellowish green and bluish green, and the absorption spectrum is typical of emerald. Chelsea-filter reactions range from pink to red; ultraviolet fluorescence is usually suppressed, attributed to iron, although some specimens fluoresce red and the response under a Stokes fluoroscope is more conspicuous. The principal diagnostic evidence comes from inclusions and internal fractures. Gübelin describes frequent basal cracks, intersecting fracture systems, healed fissures, and liquid-filled cavities or negative crystals, commonly containing two phases and forming dense featherlike patterns. Biotite is the most abundant mineral inclusion, occurring as isolated plates, clustered books, or material extending inward from the matrix, sometimes altered or strongly resorbed. Other identified inclusions include tremolite, tourmaline, apatite, epidote, sphene, and rutile. Emeralds associated with tremolite-bearing rocks are generally clearer and less fractured than those from biotite schist, though often more bluish, and contain green needles, rods, or blades that may cross the entire crystal, terminate internally, form bundles, or bend. Gübelin regards the appearance of these tremolite inclusions as especially characteristic of Habachtal and valuable for recognizing cut stones, while acknowledging resemblance to amphibole inclusions in Ural emeralds. Photomicrographs document the inclusion assemblages, supporting the article’s central connection between geological environment, internal features, and the assessment of geographic origin.

China, central Asia, Marco Polo, gems

Shor recounts her travels with her husband, Franc, in an attempt to retrace Marco Polo’s route from Venice to China, combining personal adventure, historical comparison, and observations of societies undergoing rapid political change. Opening with a dangerous episode in the Pamirs, where Franc lies seriously ill, she returns to her childhood fascination with exploration, wartime Red Cross service in Italy, and postwar relief work in China. Experiences in Shanghai and Peiping, detention by Communist forces, and a journey across the Gobi establish the background to the couple’s more ambitious expedition. Their subsequent route leads through Turkey, Iran, and Afghanistan toward the Wakhan and Hunza, using whatever transport circumstances permit, from motor vehicles to horses and yaks. Marco Polo’s narrative supplies a continuing point of reference for landscapes, trading centres, local products, and customs, although modern borders, military restrictions, and diplomatic requirements repeatedly complicate attempts to follow his itinerary. Encounters range from conversations with villagers, merchants, guides, and pastoralists to audiences and social occasions with the Shah of Iran, the King of Afghanistan, and the Mir of Hunza. Of particular gemological interest is the account of privileged access to Iran’s crown jewels at Bank Melli in Tehran. Shor describes the elaborate security arrangements, masses of loose gemstones and pearl strands, royal crowns, an emerald-topped snuffbox, a turquoise-decorated gold bowl, and the Daria-i-noor diamond. She records explanations and legends supplied during the visit concerning the treasures’ origins, acquisition, value, and role as backing for the national currency; these passages are eyewitness travel impressions and reported accounts rather than a systematic gemological catalogue. In Afghanistan, the purchase of an inexpensive piece of lapis lazuli and an unsuccessful search for a balas ruby prompt comparisons with Marco Polo’s descriptions of mineral wealth and royal restrictions on gemstone extraction and export. The expedition’s most sustained ordeal unfolds in the Wakhan, where difficult terrain, uncertain supplies, negotiations over transport, severe weather, and illness expose the travellers’ dependence on local assistance. Their intended continuation into China is ultimately prevented by political upheaval and the closure of the frontier, although they reach the crest of the Mintaka Pass before turning back. A concluding stay in Hunza provides observations of agriculture, hospitality, domestic life, government, and polo, contrasting the valley’s relative isolation with the pressures of the surrounding world. Written in an energetic, humorous, and strongly personal voice, the book presents travel as a pursuit sustained by curiosity and human generosity, while its depictions of Asian peoples and political events reflect the author’s American perspective during the early Cold War.

corundum, India.12, Ceylon, Sri Lanka.12, beryl, emerald, gems

For those who crave adventure, this book is chock full of it, a ride through various gem localities visited by the author. Although Anderton will come across to many modern readers as a bit of a Neanderthal in terms of his social sensibility, nevertheless this is a fun read.