gems, jade, pyroxene jade, fei cui, jadeite, dyed lavender jade, treated jade

Although we were aware that lavender-dyed jadeite is on the market, because we have purchased some for our collection, we have rarely been asked to identify it. Recently, we examined a bead necklace that proved to be pink-fluorescing, lavender-dyed jadeite showing a distinctive spectrum (Figure 7). The dyed stones in our collection do not show either reaction.

gems, early lapidaries, early gemology, early mineralogy, Albertus Magnus

As is well known, the much-praised Summa philosophiae, which was almost universally counted among the works of Grosseteste but cannot have been written by him, refers several times to Albertus Magnus. For these references—made without citing specific works by Albert—corresponding passages have already been identified in Albert’s writings. According to this, the relationship of the Summa to Albert consists in the fact that the author frequently considers Albert’s opinions based on his writings, generally rejects them, but occasionally—especially in mineralogy—praises his explanations. However, the identification of the texts by Albert meant by the author has not been fully satisfactory in every case, and the question remains whether the Summa’s engagement with Albert’s works might not go even further and deeper. It goes further and deeper. It can now be demonstrated which works of Albert the author of the Summa actually had in view and at hand in the passages where he refers to Albert, and how and to what extent he used them. He frequently incorporated them extensively into his own work—not merely quoting them sentence by sentence, but often copying them so fully that entire chapters are little more than extracts from a work by Albert. This order of presentation, however, does not reflect the order of discovery; in this case, recognition of dependency preceded the identification of the citations. The result will likely have less impact on the dating of the Summa than on its evaluation, which in the future will probably be more tempered than it has been up to now.

corundum, sapphire, Umba Valley, Tanzania.12, East Africa, gems

corundum, ruby, Tanzania.12, East Africa.12, gems

Bank describes a ruby-bearing zoisite-amphibolite from Tanganyika (present-day Tanzania), a material that had recently attracted attention both mineralogically and as an ornamental stone. The rock consists principally of green zoisite and dark amphibole containing conspicuous red to purplish-red ruby crystals, producing the striking color contrast characteristic of the material. The constituent minerals and their physical and optical properties are examined, with particular attention to the ruby and zoisite, and the occurrence is considered in relation to its geological setting and mineral associations. The paper discusses the identification and gemological characteristics of the material and its suitability for cutting and polishing, documenting an unusual natural association in which ruby occurs embedded in a contrasting green zoisite-rich matrix.

gems, ancient gemology, ancient jewelry, Egypt, Egyptian jewelry

The majesty and splendor of ancient Egypt were largely due to the remarkably advanced technological skills developed by its artisans and craftsmen. This comprehensive and detailed study of ancient Egyptian technology meticulously documents how these workers, along with other Egyptians, exploited the land’s abundant resources. First published in 1926 and later revised and enlarged, this monumental work became a standard reference, unmatched in any other field of archaeology. The present volume reprints the fourth edition, thoroughly revised in light of more recent research and archaeological discoveries. Topics covered include a wide range of materials and techniques central to Egyptian life: the use of animal products, building materials, cosmetics, perfumes, incense, fibers, glazed ware, glass and its production, metals and alloys, painting materials, pottery, woodworking, precious and semi-precious stones, distillation of alcoholic beverages, and substances used in mummification. Profoundly erudite and rich in detail, Ancient Egyptian Materials and Industries is an indispensable reference for students of Egyptology and classical civilizations, and a vital resource for anyone interested in the long and remarkable history of technological innovation. Sinkankas: Drastically revised, rearranged: the substances now include beverages, animal products, building materials, cosmetics, perfumes & incense, ceramics & glass, fibers, metals & alloys, mummification materials, oils, fats, waxes, painting materials, pottery & its manufacture, gemstones, other stones, woods & woodworking, and a historical analysis. Ch 12, [335–54], on gemstones, among which now additionally appear coral, amber, malachite, and jade, while horn, ivory, nacre and tortoiseshell are described in Ch 2. Ornamental stones are treated in Ch 13, [355–75]. The author notes that “diamond, opal, ruby and sapphire were not known to the ancient Egyptians.” In his preface, Harris notes the inclusion of information taken from recent studies, with references added to the list in the previous edition. Much technological information is also added, with an appendix of reliable chemical analyses. “The most consistent modification has, however, been in matters of lexicography, in order to eliminate invalid evidence derived from inaccurate or disputed translations of Egyptian texts.” In this connection, see also Harris’ Lexicographical Studies in Ancient Egyptian Materials, 1961. In this edition, the following places are of gemological interest: beads, Ch 4, [41–7] (includes gemstone materials); inlaid gemstone eyes, Ch 7, [98–127] (many types & examples); gemstones in general, Ch 16, [386–405]; other stones, Ch 17, [406–28]. Lucas should always be consulted whenever one writes or lectures about Egyptian jewelry.

corundum, gems

corundum, Tanzania.12, gems

gems, history of gemology, history of mineralogy, Greek, Greece, Rome

Diodorus Siculus, Greek historian of Agyrium in Sicily (ca. 80–20 BC), wrote forty books of world history, called Library of History, in three parts: mythical history of peoples, non-Greek and Greek, to the Trojan War; history to Alexander's death (323 BC); history to 54 BC. Of this we have complete Books 1–5 (Egyptians, Assyrians, Ethiopians, Greeks) and Books 11–20 (Greek history 480–302 BC); and fragments of the rest. He was an uncritical compiler, but used good sources and reproduced them faithfully. He is valuable for details unrecorded elsewhere, and as evidence for works now lost, especially writings of Ephorus, Apollodorus, Agatharchides, Philistus, and Timaeus. The Loeb Classical Library edition of Diodorus Siculus is in twelve volumes.

corundum, ruby, sapphire, Tanzania.12, East Africa.12, inclusions.5, gems

beryl, Lechleitner, synthetic corundum.7, Chatham, gems