Russian Gemstones Encyclopedia

Vladimir Bukanov. Russian Gemstones Encyclopedia



IVORY (ElfenbeinIvoireКость слоновая), BONE (Knochen—Os—Кость) There is also description of following types of bone, used in jewelry – dentinal ivory and bones of vertebrates.

Composition & Properties. This is a biomineral formation of the group of the corneous materials. Calcium hydroxyl phosphate in the composition with an organic substance. Amorphous. Hardness 2-3, for tusks of mammoth and mastodon – up to 5. Density 1.7-2.0; for tusks of mammoth and mastodon – up to 3.0. Dull luster. Non-transparent. Dentinal ivory: 1) Tusks – elephant’s tusks, mammoth tusks, mastodon’s tusks, wild boar’s tusks, bear’s tusks, dog’s tusks, hippopotamus’s tusks, narwhal’s tusks, tiger’s tusks, walrus’s tusks, wolf ’s tusks; 2) Teeth – white bear’s teeth, cachalot’s teeth, sea cow’s teeth, crocodile’s teeth, elephant’s teeth, hippopotamus’s teeth, horse teeth, mammoth teeth, shark’s teeth, and others.

Elephant ivory is the most precious ornamental material. Not rarely, they use this name for some other bones, however, the name can be used correctly only for tusks of modern elephant. It is a traditional material for carving and jewelry manufacturing; sometimes it is also called elephant horn. The best rough material of even pale or white color with greenish tint is called green ivory, there is from tusks of African elephants inhabiting territories of Tanzania, Kenya, Angola and Ethiopia. They reach 3.5 m. long and up to 100 kg. weight. According the character of processing, they classify hard ivory of Angolan elephants with lustrous, glassy surface of their tusks. Opposite to it, is soft ivory from tusks of elephants from Zambia and Mozambique. An average in hardness is Thai ivory, or bastard ivory of yellowish-white color with beautiful structure. Indian elephants have tusks of less size. Ivory is characterized with fine cream color, density, easiness in processing and polishing. A typical feature of ivory and mammoth ivory is a pattern of curved cross lines, obvious on the basal slabs of a tusk. These lines resemble engraving on a watch-lid. Products from ivory are known which were carved from a piece of a tusk more than 60 cm. long and 15 cm. in cross-section. In the British Museum, London, they expose fragments of elephant tusks 3.28 m. long and 102.7 and 107 kg. weight. In the Smiths. Inst., Wash., there are tusks 3.6 and 3.77 m. long and 132 kg. weight. Elephants’ molars are also used by bone carvers for small adornments and incrustations. Because of the reduction of the population of elephants, since 1989, world trade of ivory has been prohibited.

Mammoth ivory is similar to real ivory in properties and outer characteristics. Mammoths were living in Europe, Asia and North America from 100 to 4 millennium ago. In the 18-19ss cent., Russia sent mammoth ivory to the world market; this material was classified as the fifth sort of ivory (there were six sorts at all) under the trade name Moscow ivory or mammoth tusks. Their length on the average reaches 2.5 m. and weight of 50 kg. The longest of them were 4.5 m. with the biggest diameter of 20 cm. and the weight of 120 kg. The most part of extracted mammoths tusks have a great amount of cracks, and only some of them are available for processing. Color of these ivory is from white to yellowish and brown, because of the level of their mineralization. So, Siberian ivory is white, ivory from Alaska and Great Britain is brown. Mastodon ivory of the animals, which became extinct in the Pleistocene epoch, can be characterized as two pairs of oblong incisors from the upper and lower jaws. If it is well preserved, it can be rather valuable ornamental rough material. Its color is from light brown to dark brown, it displays pearl luster.

Walrus’s tusks, or sea ivory, fish tooth. They often use this name as a general one for teeth of sea mammals: walrus, narwhal, cachalot and also for shark teeth. Walruses inhabiting the shore regions of Arctic have tusks in the upper jaw – walrus’s tusks about 0.7 m. long, more rarely up to 1 m. long. Their color is light yellow to cream; their luster is silky to porcelain, the texture if fibrous. It is a traditional material for bone carvers from the Chukchi Penin. and for Eskimo from Alaska. This bone can be colored green with copper salts and after it this material resembles jade. A good material for carving is conic in the shape cachalot’s teeth without dental enamel, from 15 to 50 cm. long, as well as whale’s bone – usually they are lower jaws. Less valuable is spiral-like spike of a narwhal’s tusks of a dolphin-like Arctic whale. It is hollow inside; it is up to 2-3 m. long with the diameter up to 8 cm. Its color is uneven, from white to yellowish-brown. It displays porcelain luster, uneven, stripped texture. Although it is without dental enamel, it possesses the higher level of hardness than bone and it can be easier polished. Fossil shark’s teeth are also used as souvenirs and amulets. They serve as an official symbol of the Georgia State, the U.S.A.

Wild boar’s tusks can reach 24 cm. long. For adornments they use bear’s tusks up to 5 cm. long, too. On Alaska polar bear’s tusks served as cash; on New Guinea they used dog’s tusks for the same purpose; and on islands of Southern seas – wild boar’s tusks. Hippopotamus’s tusks are known among bone carvers under the name of sea horse ivory. Their length is 12-15 cm., their weight reaches 1-3 kg. In Japan there are popular trinkets, which came from China; they are called netsuke, from “ne” – root and “tske” – to attach. They are intricately cut figures from ivory, horns of the deer, buffalo horns, wild boar’s tusks, as well as bear’s tusks, wolf ’s tusks and tiger’s tusks and other dentinal ivory . After a while, the assortment of materials for netsuke got wider.

Odontolite, from Gk. “odontos” – a tooth and “litos” – a stone – fossil teeth and fossil bone, replaced with turquoise, vivianite and fine-crystalline apatitecollophane. Properties of odontolite: hardness – 5, density – 3-3.2, wax luster. If there are obvious concentric zones, odontolite has the trade name serpent’s-eye. Odontolite can be imitated with calcinate cow bone – oxalite, sodden with solutions of copper salts.

Synonyms. Osteolith, from Gk. “osteon” – a bone and “litos” – a stone | Osseous stone | Toad stone | Turquoise tooth | ~ turquoise: animal ~, bone ~, fossil ~, occidental ~, new stone ~, and tooth ~.

Bone. This is a bio-mineral formation of the group of the corneous materials. There is a description of following kinds of bones here: cattle bones, lower jaws of whales, fossil petrified dinosaur’s bone and fish bone. Bones from skeletons of big vertebrates are used in engraving, manufacturing of small ornamental products and even in jewelry – for rings, bracelets and brooches. So, deer’s bone, which doesn’t get yellow after some time as it happens with ivory, is used in Finland for beads. From camel bone in the East they make crosses, daggers’ and swords’ hilts. They use bones from elephant’s feet and its ribs for different products. Fossil petrified dinosaur’s bone is used for manufacturing of carved work of art in the U.S.A. A typical feature is its silicification, which is the reason of especially high hardness. Fish bone is a hard palate of some fishes from the family of Sparidae. Because of the specific of their nutrition, tumors are growing on hard palates of these fishes; they display beautiful concentric-zoned patterns with silk luster when polished.

Treatment. Every civilization began its development with usage of bone as an implement and an amulet, with making carved adornments and cult objects from it. The most ancient bone adornments were made about 3,000 B.C. Archaeologists possess data that even in the late Stone Age mammoth and elephant’s tusks were straightened to make spikes up to 2.5 m. long. Plates of ivory were used for the decoration of hilts. Pendants from teeth decorated clothes. There is information that the throne of the King Solomon was made from ivory and richly decorated with gold and gemstones. In Ancient Greece, a technology of softening of ivory was known, which is lost now. In the 5th cent. B.C., Ancient Greek sculpture Phidius covered the statue of Athena, 12 m. high, in Parthenon with plates of ivory and gold, and then, – the statue of Zeus in Olympia, 14 m. high. In the collection of the Louvre, Paris, there are numerous carved works of art from ivory by masters from Ancient Egypt, China, India and Japan. In the 11-13ss cent., in Europe, bone carving reached it’s flourishing in the manufacturing of cult objects, mainly, folding travel altar-pieces, depiction of saints and Madonna, crucifixions and rosaries. In Germany, in the Grün. Gew., Dresden, there are works of art by German masters, carved on a complete piece of ivory: including the “Faraneze Ox”, about 40 cm. high, a sculpture “Venus at the Mirror”, 30.5 cm. high, a bowl 38.7 cm. high and a bowl of ivory and gilded silver about 54 cm. high. Besides, there is an icon of the apostles John and Paul carved from ivory, 25x13.4 cm. in size, by a Byzantium master of the 10th cent.; and also there is a unique masterpiece there – the “Snake Tree”, 19.5 cm. high, by a master from Nuremberg, 1500, with shark’s teeth and gilded silver. In France, in Dieppe, there is a Museum of Ivory Works of art. In China, bone carvers make full-volume, three-dimensioned works of art of the type of “a ball inside a ball”. In Japan, they carve traditional figures netsuke from bone.

In Russia, there were local schools of bone carving in the Arkhangel’sk Region – in Kholmogory, as well in Tobol’sk, Yakutia and on the Chukchi Penin. In the collection of the State Museum of Moscow, there are ivory and bone work of art richly decorated with carved miniatures. When a fashion on fans was at the peak, the most expensive of them were made from carved ivory and decorated with gold. Besides, there were fans from tortoise shell with brilliants and pearls. In the Armory Museum Kreml., Moscow, there is a wine-horn from ivory, 63x36 cm. in size, by German masters of the 16-17ss cent. In 1710, Peter the Great decided to erect a column from ivory to celebrate the victory over Sweden. The project was worked out and ten tusks were ordered for this column, but it hasn’t been made.

Nowadays, ivory and bone are used for beads, bracelets and small plastic. The greatest center of ivory trade is Hong Kong. In 1980s, at the world market, they have sold up to 900 tons of ivory on the sum of $500 million per year. After a while, ivory gets yellow, that’s why ancient produce are evaluated higher, as usual, although there are cases of artificial ageing of ivory. Even in Ancient Egypt and Greece, they used the property of bone to be dyed. The color of elephant’s and mammoth tusks can be transformed with heating or irradiation, as well as with methods of artificial dying or whitening. Whitening with strong oxidants can produce cream-yellow or white color which are the most valuable.

Similarity & Imitations. For imitation of more expensive kinds of bones and ivory, they use bones from skeletons of different animals, as well as yellowish petrified bone or grave bone, which is called chicken bone jade in China. Popular is also artificial ivory from various plastics: avory is made on the base of celluloid polymeric material; ivorine is a plastic with admixture of bone powder and fragments of bones; and black ivory is made from pressed and dyed bone powder. Similar imitations are Congo ivory from South Africa and synthetic ivory from Japan. Another type of imitation is vegetable ivory as well as forming from gypsum with the waxed surface. Products from horn look like bone (See: Horn).