ekanite, gems

Gübelin gives a detailed gemological account of ekanite, a newly recognized metamict gem mineral from Ceylon, named for F. L. D. Ekanayake, who first recognized its unusual character. The material occurs in the gem gravels near Ellawala, northeast of Ratnapura, and is typically greenish-brown to yellowish-green, transparent to translucent, and sometimes displays chatoyancy or asterism caused by oriented clouds of minute inclusions. Gübelin describes its gemological properties, including its singly refractive character, refractive index of about 1.595, specific gravity of about 3.28, and weak absorption bands, together with microscopic features and inclusions. Chemical investigation showed calcium, thorium, silicon, aluminium, and lead, while measurements demonstrated significant radioactivity associated particularly with thorium. The destruction of the original crystal lattice through radioactive decay accounts for its metamict condition. Gübelin also discusses its probable original crystalline state, chemical composition, and age as estimated by thorium-lead dating, establishing ekanite as an unusual new addition to the gem minerals of Ceylon.

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

This is a Hindi translation of Ṭhakkura Pherū’s medieval Ratnaparīkṣā, a treatise on the examination and evaluation of precious stones. Pherū, a Jain scholar and professional assayer active in northern India around the beginning of the fourteenth century, composed the work as a practical account of contemporary gem knowledge. It describes and classifies precious stones and discusses their characteristic qualities, defects, varieties, provenance, and criteria used in judging them, reflecting the commercial as well as traditional Indian approach to gem testing. The work belongs to Pherū’s group of technical treatises dealing with such subjects as metals, assaying, mathematics, and material commodities and is an important source for the history of gemology and the gemstone trade in medieval India. The bibliographic record needs correction: available cataloguing identifies Agar Chand Nahata and Bhanwar Lal Nahata with the Hindi translation, rather than Ratna Pariksha as the author; one bibliographic source records the 1962 Hindi translation as published by Abhay Jain Granthalaya, Bikaner, while another scholarly bibliography lists the Hindi translation as published in Calcutta without a date, so I would not retain “Calcutta: Nahata Brothers; 168 pp.” without checking the title page.

gems, archaeology, archaeogemology, China, Southeast Asia, Thailand, Laos, Cambodia, Vietnam

Malleret presents the first volume of his major archaeological study of the Mekong Delta, devoted to the exploration and excavations of Oc-Èo in southern Vietnam, a principal archaeological center associated with the ancient kingdom of Funan. He describes the history of archaeological investigation in the delta, the identification and topography of Oc-Èo and neighboring sites, and the results of excavations and surface surveys, including architectural remains, canals and other landscape features, religious monuments, sculpture, ceramics, stone implements, and other finds. Particular attention is given to the extensive settlement remains and their relationship to the wider Transbassac region, providing the archaeological foundation for the subsequent volumes dealing with the material culture of Oc-Èo and the culture of Funan. The work comprises xii + 473 pages with 72 figures and a separate section of 97 plates.

gems, gems, jade, jadeite, fei cui, Mesoamerica, Mexico, Guatemala, Costa Rica, Mayans, Olmecs, Aztecs, archaeology, history, archaeogemology, Pre-Columbian jade; Costa Rica; Maya; exchange; iconography, lapidary, tribute indians paid to Moctezuma

The document published here by Francis V. Scholes and Eleanor B. Adams is the first systematic commentary on the Aztec tribute rolls to emerge from the sixteenth century. It consists of the court testimony of six Tlatelolco principales in 1554 regarding the tribute paid to Moctezuma. The witnesses commented upon an actual tribute roll of the Matrícula de Tributos type, and their observations provide important new evidence for reconstructing the Aztec imperial system and the tribute exacted from subject provinces. The imperial provinces appear in the order found in both the Matrícula de Tributos and the Codex Mendoza. The tribute roll examined by the witnesses evidently contained many more town names than are preserved in either of the two rolls known today, a fact that supports the frequently expressed view that the Matrícula de Tributos and the Codex Mendoza are incomplete. The testimonies record the number of towns in each province, although, except in the case of Petlacalco, where some names are given, the towns themselves are not identified. The editors also offer new interpretations concerning the quantity and nature of the tribute, festival obligations, the frequency of payments, land tenure, succession, and the mid-sixteenth-century value of the tribute formerly paid. The document is an important one, but it is the reviewer’s duty to object to an edition so limited that individual copies are sold at 200 pesos. — Charles Gibson, University of Iowa.

gems, gemology,

Chudoba and Gübelin provide a compact practical reference to gemology intended both for identifying gemstones and for standardizing the often confusing terminology used in the German gem trade. The principal gemstones and ornamental materials are arranged alphabetically and characterized by their chemical, crystallographic, and physical properties, important localities, trade names, and diagnostic features. Separate sections treat inclusions in natural gemstones, synthetic stones, doublets and triplets; tables of gemological constants; coated stones; synthetic gems and other imitations; the gemological microscope; and practical identification tables. Particular emphasis is placed on simple tests that can be performed with readily available gemological instruments and on microscopic inclusions as a means of distinguishing natural stones from synthetics and assembled or imitation materials. Conceived as a concise working handbook rather than a comprehensive mineralogical treatise, it became the basis for the substantially enlarged second edition of 1966, retitled Edelsteinkundliches Handbuch, and a further expanded third edition in 1974.

gems, jade, pyroxene jade, fei cui, Guatemala, Mesoamerica, Nicaragua, Mexico, Honduras, Costa Rica, archaeogemology

gems, Arabic mineralogy, al-Biruni, corundum, spinel, pearl, early lapidaries

Lemmlein examines the mineralogical information contained in al-Bīrūnī’s Kitāb al-Jamāhir fī maʿrifat al-jawāhir, assessing the work from the standpoint of modern mineralogy and the history of science. He considers al-Bīrūnī’s descriptions and identification of gemstones, minerals, metals, and alloys, including their colors, physical characteristics, localities, methods of extraction and working, and commercial uses. Particular attention is given to al-Bīrūnī’s quantitative investigations of specific gravity, which represent an unusually advanced experimental approach for the eleventh century, and to his attempts to distinguish minerals through observable and measurable properties rather than relying solely on traditional lapidary lore. Lemmlein also discusses the difficulties of correlating medieval Arabic mineral names with modern species and emphasizes al-Bīrūnī’s critical use of earlier authorities, craftsmen’s knowledge, and his own observations and experiments. The article presents the Jamāhir as one of the most important medieval contributions to mineralogy and gemology.

gems

gems, ancient gems, glyptic, archaeology, archaeogemology, beads, chalcedony, Harrapa, jade, feldspar, amazonite, lapis lazuli, faience, ivory, shell, brecciated jasper in chalcedony, Indian lapidary, Central Asia

At the request of Mr. Madho Sarup Vats, Deputy Director General of Archaeology in India, I have undertaken to write a chapter on selected beads from Harappa. The fact that I cannot examine the entire collection has made it difficult to assess the likelihood of foreign importation, but Mr. Vats has been of great assistance in providing details on whether each specimen is unique, rare, or common, as well as information on the stratigraphic layer in which it was found. This data, combined with a close examination of the beads, has revealed some interesting possibilities regarding connections with other civilizations, particularly the Sumerian civilization in Mesopotamia. Since there appears to be little variation among the beads from different layers—many types occurring across several layers—I have chosen to group the beads by material rather than by stratigraphy. Several plates accompany the text for clarification. The first two are diagrammatic and show the beads arranged by shape according to the Beck Method of classification. Plate CXXIX illustrates beads in Group I, those with circular transverse sections, while Plate CXXX shows beads with non-circular transverse sections. Some plates also consist of microphotographs showing internal structure. One especially notable feature of the Harappa beads is the remarkably large number made from steatite. Nowhere else has such a high proportion of beads been found in this material. Moreover, the variety of treatment applied to the steatite is quite exceptional. While some beads are in natural stone, the vast majority have undergone heat treatment that whitens the surface. These are referred to as “burnt” steatite beads. Although I cannot be certain that intense heat was used in every instance, I have adopted the term nonetheless.

corundum, ruby, sapphire, Thailand.12, gems

Credner presents a broad geographical account of Siam based on his extensive travels and field investigations, combining physical geography, geology, climate, vegetation, settlement, population, agriculture, communications, and economic development. He describes the major geographical regions of the country and relates their landscapes and patterns of human occupation to underlying geology and relief. Mineral resources and mining form part of the economic-geographical treatment, including Siam’s important tin industry and other mineral occurrences, while the gem-producing districts are considered within the wider discussion of natural resources. The work is particularly valuable as a detailed picture of Thailand in the early 1930s, shortly after the political changes of 1932, and contains numerous photographs, maps, and observations derived from Credner’s own fieldwork. For gemological purposes its importance lies chiefly in the geographical and geological context it provides for Siam’s mineral and gemstone resources rather than in detailed mineralogical descriptions.