corundum, synthetic corundum.7, Knischka, Seiko, synthetic beryl, emerald, gems

Reviews diagnostic properties of recently introduced synthetic emeralds and corundums, emphasising microscopic internal features as a practical means of distinguishing them from natural gemstones and from one another. The emerald survey covers Lennix, Biron, Soviet flux-grown and hydrothermal products, and Seiko material. Comparative tables assemble refractive indices, birefringence, density, absorption spectra, ultraviolet reactions, Chelsea-filter responses, inclusions and selected chemical analyses. Lennix emeralds display conspicuous growth channels, dark molybdenum-bearing flux residues, included beryl and phenakite crystals, and wispy or banner-like inclusion patterns. Their variable internal structures are related to changing conditions during flux growth. Biron hydrothermal emeralds contain characteristic granular veils and banners composed of fluid inclusions, sometimes spiralling around growth tubes, together with wedge-shaped inclusions, crystallites and fishbone-like growth inhomogeneities. Gübelin notes that cleaner recent production may lack the abundant inclusions seen in earlier material and cautions that some individual features also occur naturally. Infrared evidence of structurally incorporated water supports identification of hydrothermal growth. Soviet flux-grown emeralds commonly show yellowish-brown flux inclusions, granular fingerprints, phenakite and platinum crystallites, whereas Soviet hydrothermal emeralds may be distinguished by spindle-like growth streaks and intersecting zigzag patterns. Seiko emeralds contain dense layers of fine particles and slender prismatic crystallites whose precise mineral identity remained uncertain. The corundum discussion describes Seiko ruby and sapphire, Lechleitner products and newer Knischka rubies. Seiko ruby may be exceptionally clean, with only subtle swirling growth irregularities and minute flux grains. Hazy patches in Seiko sapphire can resemble the appearance of Kashmir sapphire, requiring careful assessment of their internal character and optical behaviour. Lechleitner corundums consist of natural or synthetic seeds with a synthetic coating; characteristic partly healed fissures repeatedly intersect at right angles, producing square or rectangular patterns, while metallic-looking flux remnants may occur in the coating. The article explains how synthesis procedures generate these structures and illustrates the resulting features with numerous photomicrographs. Its central conclusion is that increasingly sophisticated synthetic products still retain observable differences associated with their formation. Reliable identification therefore depends on combining physical properties and analytical evidence with detailed microscopic interpretation, particularly when familiar features are absent or resemble inclusions in natural stones.

synthetic beryl, emerald, synthetic beryl, gems

The Lennix synthetic emerald, currently n~anufacturedin France, is a dark green, moderately transparent to translucent material grown by flux fusion. With the microscope, zones of lighter and darker green are evident. For the most part, the gemological properties of this synthetic emerald overlap those of natural einer-aids, although the low refractive-index and specific-gravity values are good indi-cators that this material is synthetic. The presence of wispy veil" inclusions pro-vides conclusive proof of synthetic origin, as do the chemical analyses, infrared transmission spectra, and cathodo-luminescence."

gems, beryl, emerald, Egypt, Cleopatra, emerald geology

Geochemical rock sampling and panning of Alluvium suggest the occurrence of a geochemical province of beryllium, in which beryl is the main beryllium mineral, in the Nugrus-Zabara area. The province lies in a NW-SE belt parallel to a deep-seated tectonic zone of the Red Sea trend and extends for about 40 km from Um Kabu in the SE to Zabara in the NW. The province is restricted to certain horizons of mica schists and quartz veins in contact with greisenized and albitized stanniferous granites and is probably developed by pneumatolytic and hydrothermal fluids (developed during the evolution of stanniferous granite magma) which moved along deep-seated tectonic zones. The province is characterized by biotitization, tourmalinization and silicification of the schists and increased concentrations of Be, Sn, Nb, Pb, Y and Cu in the granites, schists, quartz veins and pegmatite dykes. The ancient emerald mines are located within the boundaries of this province.

gems, topaz, Pakistan

In addition to the relatively recent discovery of significant amounts of emerald, aquamarine, and ruby, Pakistan has also begun to produce fine gem-quality pink topaz. In a small hillock of recrystallized limestone north of Katlang, narrow calcite veins encase pink topaz crystals up to 3 cm long, accompanied by larger amounts of reddish brown, tan, and colorless topaz crystals. More than 70,000 ct of gem-quality pink topaz has been reported to date. The refractive indices, optic axial angle, unit-cell dimensions, and density of the topaz are influenced by a partial replacement of fluorine by hydroxyl ions. The color is due to trace elements—principally chromium (Cr³⁺). Treatment experiments revealed that the color of the brown, tan, and colorless topaz from this source may be improved by irradiation and heat.

corundum, inclusions.6, synthetic corundum.7, Burma.12, gems, Kashan, Ramaura, Linde, beryl, emerald, synthetic emerald, Raman spectroscopy

By allowing positive identification of fluid and solid inclusions inside minerals, laser Raman microspectrometry has proved to be a perfect technique for discriminating between natural gems or synthetic minerals made for jewellery (sapphire, ruby, emerald)

beryl, emerald, Colombia, gems

An illustrated introduction to underwater treasure hunting that combines accounts of major discoveries with practical guidance for prospective explorers and investors. Trupp profiles Mel Fisher’s prolonged search for the Spanish galleon Nuestra Señora de Atocha, Kip Wagner’s recovery of treasures from Florida’s wreck sites, and Arthur C. Clarke’s involvement in exploring a silver-bearing wreck at Sri Lanka’s Great Basses Reef. These narratives examine the persistence, research, financing, and personal risks behind successful salvage operations. A substantial discussion considers conflicts between commercial treasure hunters and professional archaeologists over ownership, excavation methods, preservation, and public access to maritime heritage. Practical sections address personal preparation, the range of recoverable objects, investment opportunities, and the assessment of speculative ventures and fraudulent claims. Regional chapters survey Caribbean wrecks and submerged settlements, North American beaches, and the Great Lakes and Canadian waters, extending the subject from major shipwreck expeditions to recreational beachcombing. Listings of underwater organizations and research resources accompany maps, photographs, a bibliography, and an index. The volume concludes with five promotional treasure hunts linked to named destinations. With a foreword by Fisher, the book presents a mid-1980s perspective on the attraction of sunken wealth and the competing commercial, recreational, and historical interests surrounding its recovery.

treasure, Atocha, emeralds, gold, gems

jade, jadeite, fei cui, Burma, gems

A.E. Barry and G.E. Harlow examine unusually zinc- and manganese-rich chromites associated with reaction zones in kosmochlor-bearing fei cui, using mineral compositions to investigate metasomatic modification during jade formation. Specimens from Myanmar and Mocchie Susa, Italy, contain emerald-green kosmochlor, termed ureyite in the original account, in reaction textures with chromite. Comparable assemblages occur in Mesoamerican jade artefacts from Mexico and Guatemala, although the chromium-bearing pyroxene in these examples is omphacite. The authors relate these rocks to tectonically emplaced, serpentinized ultramafic bodies and interpret their interstitial chromites as inherited ultramafic grains incorporated during jade formation. A proposed reaction involving chromium spinel, albite, and sodium-bearing solution consumes chromite while producing a jadeite–kosmochlor solid solution and releasing divalent cations to solution. Chromites from the different occurrences have similarly unusual compositions, including high chromium contents and concentrations reaching 2.5 wt.% zinc oxide and 3.5 wt.% manganese oxide. To assess the changes accompanying reaction, Guatemalan jade-hosted chromites are compared with chromites from nearby jade-producing serpentinite belts along the Motagua Fault. The inferred original spinels are magnesian and fall within the normal compositional range of podiform chromites in alpine-type ultramafic rocks; serpentinization also produces aluminium-poor ferric chromites. Relative proportions of chromium, aluminium, and ferric iron in the jade-hosted grains resemble those in the least ferric original spinels. In contrast, magnesium is depleted by approximately an order of magnitude, ferrous iron is enriched about 1.5-fold, and manganese and zinc are enriched by approximately an order of magnitude. Assuming that the metasomatic fluid adds no ions to the spinel, the authors explain these changes through removal of trivalent cations during decomposition, preferential loss of magnesium to solution, and residual concentration and diffusion of manganese and zinc into surviving spinel. Crystal-chemical preferences, ionic properties, and solubility in the metasomatic fluid are proposed as controls on this selective redistribution. Zinc’s preference for large tetrahedral sites helps explain its retention relative to incorporation into pyroxene or other silicates. Reaction and solid-state diffusion are thus considered sufficient to generate the anomalous chromite compositions at estimated jade-forming temperatures of 250–400 °C. The results suggest that chromite is substantially more susceptible to divalent-cation redistribution than to trivalent-cation diffusion under these metasomatic conditions.

beryl, synthetic beryl, emerald, gems

Dr. Frederick H. Pough, noted mineralogist and gemologist, supplied Gem News with the following information concerning the Russian hydrothermal synthetic emer-alds that have recently appeared on the colored-stone market. The emeralds show a refractive index of 1.574–1.580 with a birefringence of 0.006. They do not fluoresce to either long-wave or short-wave ultraviolet radiation, and their color-filter reaction is negative. The specific gravity is above 2.67, as would be expected from a hydrothermal synthetic emerald.The emeralds show a unique chevron-shaped internal growth pattern (figure 3),which has not been observed in any natural emeralds. The emeralds are doped with iron which maslts the fluorescence. The Gem News Editor also has examined some of these Russian synthetic emeralds and his obser-vations support those of Dr. Pough.

corundum, synthetic corundum.7, gems, beryl, synthetic emerald