gems, beryl, emerald, Colombia, drug wars

Discusses the drug wars in Colombia that have often involved members of the emerald trade.

gems, inclusions, beryl, emerald, Madagascar

gems, inclusions, beryl, emerald, Australia, Norway

The second installment of Schwarz’s systematic study of the chemical properties of emeralds from different geographic sources, dealing with material from Australia and Norway. Norwegian specimens are from Eidsvoll near Lake Mjøsa, while the Australian material represents several occurrences, including Pilangoora, Wodgina, Calvert White Quartz Hill, Warda Warra, Melville, Torrington, Emmaville and Menzies. Chemical analyses are used to compare major and trace-element compositions and to evaluate variations among deposits and against previously studied Brazilian emeralds. Schwarz notes, among other distinctions, generally lower magnesium contents than in Brazilian material. The paper demonstrates the usefulness of chemical composition, considered together with gemological properties, for characterizing emeralds and assessing their geographic origin.

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

The Indian alchemical literature in Sanskrit and Tamil refers to the multi-dimensional use of a wide variety of minerals. The most important are: (A) mica, calamine, copper-pyrite, tourmaline, iron-pyrite, copper-sulphate, bitumen and lapis lazuli, called superior minerals and (8) orpiment, alum. sulphur, realgar, tinstone or cassiterite, red-ochre, antimony and iron-sulphate, called subsidiary minerals. An interesting aspect relates to the purifications of these minerals with a view to importing to them the necessary qualities for alchemical operations leading to the preparation of elixir" and such other medicinal compo itions. Yet another aspect is concerned with the extraction of what is in alchemical literature as their "essence". the chemical details of which are not exactly clear. The other types of minerals are classed under the heading gems. They are: ruby, pearl, coral, emerald. topaz. diamond, sapphire. zircon and eat's eye, nine in number. Even these gems are subjected to various processes in order to obtain their essences. Several apparatuses and contrivances were being designed and used for conducting necessary operations. Refreshingly, some of the alchemical text also mention the distribution and characteristics of various minerals including gems. thus revealing the technical knowledge of those involving the preparation of several mineral-based medicinal compositions. The paper attempts to discuss these and allied aspects pertaining in the minerals and gems as embodied in the various texts in Sanskrit, called the "Rasa.Siistra". The Indian alchemical literature in Sanskrit and Tamil refers to the multi-dimensional use of a variety of minerals. The pre-eminence of minerals as alchemical substance is first recognized in the famous sayings in Rasaratmikara of Nagarajuna of c. 8th cent. A.D. Attributing minerals with some wonderful properties of conversion of base metals into higher metals. The subsequent periods evince extensive study of minerals started with the search for essential substances for attaining perfection in preparation of elixir to a wide extent. Alchemical literature in India from c. 8th cent. A.D. onwards abounds in details of minerals and gems in regard to physical traits, places of origin in some cases, categorization into superior and inferior,"

gems, early lapidaries, beryl, emerald, jasper, quartz

The episode of the Forest of Morrois highlights three objects: the sword, the gloves, and the ring. Our aim is first to examine the last of these, which has remained relatively overlooked. The “bare sword” (v. 1987) is meant to replace the one (v. 1998) belonging to the sleeping Tristan, serving as a signum for Marc of the lovers’ innocence; its placement is emphasized. However, there is no description of the sword itself, at least not at the moment of Marc’s intrusion. By contrast, the number of lines devoted to the ring surpasses those celebrating the other object.

gems, garnet, pyrope-almandine, rhodolite, star garnet, star rhodolite, Tanzania

This article describes the first reported occurrence of asteriated rhodolite garnet from Tanzania and details the specimen’s gemmological properties. Acicular rutile crystals are well-known inclusions in almandine garnets (Webster, 1983; Gübelin and Koivula, 1986; Liddicoat, 1987), and when fashioned en cabochon, stones with a relatively dense and even distribution of these needle-like inclusions may exhibit asterism, typically as a four- or six-rayed star. Sources of star almandine garnet include India (Webster, 1983; Rohrbach, 1986) and the Emerald Creek area of Idaho, USA (Zeitner, 1986; Rohrbach, 1986). Rhodolite, a reddish-purple to purple garnet composed of a mixture of almandine and pyrope, was first described from North Carolina, USA (Hidden and Pratt, 1898), and is also found in Sri Lanka (Webster, 1983), a major commercial source (Federman, 1984). In recent decades, African localities such as Zimbabwe (Campbell, 1972), Madagascar (Campbell, 1973), and Tanzania (Phillips, 1962; Sinkankas, 1968; Sarofim, 1970; Pough, 1973) have also produced rhodolite, with Tanzania now serving as an important commercial source (Federman, 1984). Like almandine, rhodolite from several sources may contain acicular rutile inclusions (Campbell, 1972; Webster, 1983), though few references have noted these inclusions producing asterism in rhodolite (Rohrbach, 1986). The authors recently examined a rhodolite garnet cabochon that displayed a four- or six-rayed star, depending on the viewing angle. The stone was cut from rough purchased and fashioned by Mr. Barton Curren of Glyptic Illusions, Topanga, California, USA, from a Tanzanian parcel reportedly originating from the Kangala mine. According to Curren, the rough was relatively inexpensive due to its higher inclusion content compared to other Tanzanian rhodolite he had previously acquired.

gems, beryl, emerald, Colombia, chemistry, geology

Emerald deposits of Colombia are confined to lower Cretaceous shales of the Eastern Cordillera. The tectonic pattern of the deposits is related to deep reverse and large regional fault systems. Hydrofracturing is the main factor controlling emerald mineralization. It permitted to the hydrothermal solutions to permeate through fractures but also along stratification planes forming in this case stratabound mineralizations. Emerald occurs in calcite veins, veinlets, pockets and brecciated zones associated mainly with pyrite, quartz, parisite, codazzite and fluorite. Emerald mineralization belongs to an epigenetic hydrothermal process. The alternance of arenite-shale formations in the Cretaceous probably played an important role in the accumulation of solutions and in the propagation of the hydrothermal channels. The origin of emerald involves chemical elements mobilized by the fluids in the Cr-V-Fe-Al-Si-bearing black shales. The source of beryllium remains a problem and is discussed in the paper.

gems, beryl, emerald, Colombia

Coffee-table style photo essay on the emeralds from Colombia, with some lovely photography of the mines at Muzo, markets, trading and cutting in Bogota. The last few pages offer a bit of gemological information about emerald and where it is found around the world. This book is valuable mainly for the photos.

beryl, synthetic beryl, emerald, gems

gems, beryl, emerald, Brazil, Santa Terezinha

Emeralds from Santa Terezinha de Goiás, a major global producer, contain a diverse range of primary inclusions identified through X-ray diffraction, energy dispersive analysis, and electron microprobe techniques. These inclusions include chromite, dolomite, magnesite, talc, phlogopite, pyrite, quartz, beryl, barite, patronite, ferropargasite, anthophyllite-cummingtonite, epidote, melanterite, and dumortierite, which reflect the metamorphic nature of the host rocks. Chromite, the most characteristic inclusion, appears as isolated or clustered idiomorphic crystals that exhibit a distinctive red-brown hue under magnification. Carbonates like dolomite and magnesite occur as rhombohedral crystals, while talc is present as dispersed flakes. Other notable inclusions include yellow cubic pyrite, phlogopite (less common than in emeralds from Itabira and Socotó), idiomorphic beryl, and quartz filling fractures. Barite and patronite are rare, while epidote, cummingtonite-anthophyllite, dumortierite, and melanterite were detected only in mixtures via X-ray methods. Fluid inclusions, visible only at high magnifications, contain gas, liquid, and solid phases. The observed inclusions align with the paragenesis of the metamorphic country rocks, and chemical analysis indicates significant variations in the crystallization conditions of these emeralds.