jade, jadeite, fei cui, nephrite, Burma, China, jade carving, Chinese jade, gems

W.L. Hildburgh examines Chinese snuff-bottles carved from parti-coloured hardstones, emphasizing the lapidary’s ability to transform natural layers, stains, inclusions, and irregularities into coherent decorative designs. Extending an earlier discussion of Chinese hardstone carving, he argues that these small utilitarian objects often display exceptional artistic invention alongside technical mastery. He explains that the exterior is completed before hollowing begins, allowing the craftsman to investigate colour distribution, exploit useful features, and remove defects before undertaking the lengthy excavation of the interior. Reports from carvers using treadle-driven tools suggest that shaping and ornamenting a fine bottle could require ten to fifteen days, with another ten to thirty days devoted to hollowing and internal polishing. Thin walls enhance translucency, reduce weight, and demonstrate skill, while the precision achieved inside opaque or awkwardly shaped vessels reflects sophisticated control of tools and material. Hildburgh distinguishes several approaches to coloured decoration. Contrasting layers may be carved in rounded cameo relief against a relatively uniform body, as in agate bottles bearing horses, birds, bamboo, or a cricket among vegetables. Rock crystal with adhering white quartz matrix provides another combination, with the matrix shaped into trees, animals, and figures; one smoky-quartz example retains the crystal’s natural hexagonal form beneath carved decoration on all six faces. More complex stones permit the coordination of several coloured strata, variations in translucency, and differentiated polish within a single composition. Hildburgh also notes that separately carved reliefs may be cemented over flaws so skilfully that the repair is difficult to detect. Where colour occurs only in a thin surface concentration, the carver must preserve its irregular level and avoid rounding edges that would expose the underlying body colour. The article’s most sustained analysis concerns agates containing dispersed dark markings. Here the craftsman selectively lowers and shapes the surface to reveal coloured areas at different depths, adjusting their contours and opacity to create silhouettes, figures, foliage, birds, and landscape effects. Some natural formations remain untouched, while others are integrated with carefully worked details. Hildburgh contrasts this responsive manipulation with European uses of patterned stones, crediting Chinese carvers with an unusually sensitive appreciation of each specimen’s individual possibilities. Throughout, he stresses that photographs inadequately convey many effects dependent on subtle colour, translucency, depth, or decoration extending around the vessel. The study presents successful snuff-bottle carving as an accommodation between the demands of handling, the geological character of the stone, and the craftsman’s imaginative interpretation.

corundum, synthetic corundum.7, synthetic spinel, inclusions.5, gems

beryl, emerald, Russia, Colombia, inclusions, gems

corundum, properties.3, gems

Walcott investigates asterism in garnet, spinel, quartz and sapphire through microscopic observations, measurements of angular relationships, and geometrical reconstructions of luminous bands on spheres and crystal models. His principal aim is to relate star patterns to crystallographic symmetry and to identify the internal structures responsible for their formation. Two almandine garnet spheres in the Field Museum display four great-circle chatoyant bands intersecting to produce twelve four-rayed stars, each with alternating angles of 70°32′ and 109°28′. These bands are associated with fine elongated inclusions oriented parallel to the crystal’s threefold symmetry axes. A garnet cabochon possesses an additional inclusion system parallel to the fourfold axes, producing a combination of four- and six-rayed stars. A dark-red spinel cabochon contains inclusions aligned with the twofold symmetry axes; projected onto a complete sphere, its six bands would generate eight six-rayed stars with 60° angles and six four-rayed stars with 90° angles. These observations directly challenge the assumption that cubic minerals can exhibit only four-rayed stars with right angles. Walcott develops a classification of possible inclusion arrangements parallel to the three classes of symmetry axes in the hexoctahedral crystal class, considering both complete and incomplete sets and their combinations. He calculates a minimum of 179 possible arrangements, while distinguishing the few represented by available specimens from hypothetical configurations. The most elaborate configuration considered would produce thirteen great-circle bands and combinations of six- and eight-rayed stars. Turning to colourless quartz, rose quartz and sapphire, he describes three intersecting bands forming six-rayed stars at the poles of the crystallographic c-axis. Restricted illumination reveals fine internal striae that he interprets as surface growth striations incorporated into the crystal during oscillatory development of different crystal forms. In sapphire, he further suggests that some striae lengthened through minute cracks associated with metamorphism. He attributes the greater abundance of star sapphires than star rubies to differences in prevailing crystal habits and their propensity to develop striations. Variations in the fineness, continuity and arrangement of these structures are used to explain sharply defined, broad or feathery star bands, while zoning, twinning and other inclusions may diminish their brightness. A predominantly single directional system can produce a sapphire cat’s-eye when appropriately cut. Throughout the study, Walcott interprets asterism chiefly as a diffraction phenomenon, supported by transmitted-light stars in quartz and spectral colours observed in sapphire bands. The paper combines documented observations with geometrical predictions and proposed explanations for the origin of the structures producing the optical effects.

gems, Arabic mineralogy, al-Biruni, rock crystal, glass

Kahle presents and translates sections of al-Bīrūnī’s eleventh-century Kitāb al-jamāhir fī maʿrifat al-jawāhir dealing with rock crystal, glass, enamel/glass fluxes (mīnā), and ruby glass (adrak), using two manuscripts and emphasizing the value of al-Bīrūnī’s account for understanding the materials and techniques represented among the Fatimid treasures. Rock crystal is described as a transparent, colorless stone prized for vessels, hardness, clarity, and resemblance to water and air; al-Bīrūnī discusses its sources, working, value, inclusions, and supposed formation, including contemporary observations and historical anecdotes concerning valuable crystal vessels. Glass is described as produced by melting quartz or sand with alkali, prolonged firing increasing its clarity and hardness; properly made colorless glass could approach rock crystal in transparency, though its greater abundance and softness reduced its value. Particularly important is al-Bīrūnī’s treatment of mīnā, explicitly described as a type of glass, softer and heavier according to its lead content. He records recipes employing finely powdered quartz or rock crystal with red lead or tin oxide, together with natron or borax-type fluxes, and gives coloring materials: lead compounds for yellow, copper compounds for green, burned brass for red, iron residues for black, manganese for wine-purple, lead white for white, burned gold for ruby color, and lapis lazuli and carnelian for violet. Kahle notes that these descriptions strongly support the interpretation of mīnā in Fatimid inventories primarily as enamel or vitreous flux. The final section discusses adrak, an ancient Alexandrian red or garnet-colored glass reportedly comparable in appearance and value to ruby and whose manufacture was said already to have been lost by the ninth century; al-Bīrūnī preserves several recipes or traditions for attempting its production, along with observations on other artificial colored materials, mosaics, and objects recovered from ancient Egyptian and Yemeni burials.

corundum, inclusions.5, Afghanistan.12, Tajikistan.12, gems, lapis lazuli

Describes lapis lazuli, spinel, and ruby occurrences in the crystalline limestones and marbles associated with Afghanistan’s extensive metamorphic formations. The Badakhshan lapis lazuli deposit lies in the upper Kokcha valley, about ten kilometres downstream from Robat, where mineralization locally replaces the enclosing marble. Barthoux records three commercial colour varieties and describes extraction by heating selected portions of the rock with fires, followed by ventilation and removal of the loosened blocks. Lazurite crystals reaching 15 mm occur in the surrounding white marble, accompanied by phlogopite, humite, forsterite, and pyrite; crystallographic details are provided for several minerals. Historical balas rubies from Gharan, near Siz on the right bank of the Oxus, are described as large, slightly cloudy, violet-pink spinel octahedra, distinguished from almandine obtained across the river. At Jagdalak, between Kabul and Jalalabad, steeply inclined marbles contain abundant spinels of various colours together with pink corundum. The paper describes the crystal forms of the corundum and associated minerals, including humite, chondrodite, phlogopite, fuchsite, rutile, titanite, hematite, pyrite, and diopside. Emerald-green pargasite occurs as isolated crystals or aggregates with phlogopite, and a chemical analysis is reported for comparison with edenite.

corundum, inclusions.5, Burma.12, Sri Lanka.12, Thailand.12, gems

Escard provides a concise survey of the ruby, describing its varieties, physical properties, geographical sources, mining, cutting, valuation, and methods of distinguishing natural stones from imitations and artificial products. [655] He identifies ruby as red corundum and discusses differences in color among rubies from Burma, Siam, and Ceylon, noting that terminology such as “Oriental ruby” and “Siam ruby” was often applied inconsistently in commerce. [656] Particular attention is given to microscopic examination: natural rubies may contain crystalline inclusions and other internal features, while differences in color and dichroism can help separate stones from different sources; illustrations show characteristic inclusions and a Ceylonese lapidary at work. [657] Escard discusses the distinctive internal structure of Burmese and Siamese rubies, differences observed with the dichroscope, and variations in specific gravity, accompanied by photomicrographs and a map of the ruby-bearing district of Burma. [658] Fluorescence and phosphorescence are described as useful diagnostic properties, Burmese rubies showing particularly strong fluorescence; the principal ruby deposits are said to occur in Burma and Ceylon, where ruby-bearing gravels are washed and sorted, with an account of mining and recovery methods in the Mogok district and illustrations of the Burmese mines. [659] The article gives production and value figures for Burmese ruby mining, mentions occurrences in Ceylon, Siam, Afghanistan, and elsewhere, discusses the considerable variation in value according to color, quality, and size, and briefly describes cutting practices, including the preference for the oval form. [660] Escard concludes with remarks on celebrated rubies, including stones associated with European collections, and emphasizes the commercial importance of distinguishing natural rubies from artificial stones, illustrating a certificate of authenticity for a natural Burmese ruby.

corundum, synthetic corundum.7, gems

Heaton reviews the contemporary production of artificial precious stones and the methods available for distinguishing them from their natural counterparts. Particular attention is given to synthetic ruby and sapphire, including the processes developed by Frémy and Verneuil, the materials and apparatus employed, and the physical and optical properties of the resulting products. The paper discusses the identification of artificial stones by microscopic examination, inclusions, internal structure, and other diagnostic characteristics, and considers imitation and reconstructed stones alongside true synthetic products. Published at a time when flame-fusion corundum was becoming commercially important, it provides a useful contemporary account of the problems that synthetic gemstones posed for jewelers and gemologists.

gems, corundum, inclusions.5, synthetic.7

Small booklet describing how to separate natural rubies from the newly developed synthetic rubies.

corundum, USA.12, North Carolina.12, Montana.12, gems

Kunz reviews the precious-stone industry and trade in 1887, beginning with American gem mining and estimated U.S. production, then describing recent discoveries and developments involving diamond, zircon, beryl, phenacite, garnet, tourmaline, hiddenite, rock crystal, chrysoprase, agate, pectolite, feldspars, rhodonite, turquoise, cyanite, labradorite, and ornamental stones. Kunz-1888-Precious stones.pdf A substantial section treats foreign sources, particularly the rapidly expanding South African diamond mines, their mining and sorting methods, production, values, consolidation, and effects on the international diamond trade; Kunz also discusses Brazilian, Indian, and Australian diamond production and the growth of diamond imports, cutting, and consumption in the United States. Of particular gemological interest are detailed accounts of the Kashmir sapphire deposit, discovered in 1882 in the Zanskar Range, and the Mogok ruby mines of Burma, including British attempts to lease the mines, contemporary mining practices, royalties, and trade. Kunz also surveys changing fashions in gems, including cat’s-eye, alexandrite, moonstone, opal, and amber, and notes the rapidly growing American interest in carved jade and other hardstone objects. He discusses Alaskan jade, Central American jadeite artifacts, Burmese jadeite, and Māori jade objects, while recording contemporary theories concerning the provenance of American jadeite. The report concludes with accounts of important gem collections and their dispersal or acquisition, including the Hope collection, the French Crown jewels, C.W. King’s engraved gems, the Sommerville collection, W. Hayes Ward’s ancient cylinders, and Isaac Lea’s collection of gems studied for microscopic inclusions.