Oltu stone () is a kind of jet found in the region around

Oltu Oltu (; ) is a municipality and district of Erzurum Province, Turkey. Its area is 1,441 km2, and its population is 30,075 (2022). The mayor is Adem Çelebi, from the AKP. History An inscription found in Oltu's castle has been dated to the 7t ...

town within

Erzurum Province Erzurum Province () is a province and metropolitan municipality in the Eastern Anatolia Region of Turkey. Its area is 25,006 km2, and its population is 749,754 (2022). The capital of the province is the city of Erzurum. It is the fourth lar ...

, eastern

Turkey Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armen ...

. The organic substance is used as semi-precious

gemstone A gemstone (also called a fine gem, jewel, precious stone, semiprecious stone, or simply gem) is a piece of mineral crystal which, when cut or polished, is used to make jewellery, jewelry or other adornments. Certain Rock (geology), rocks (such ...

in manufacturing jewellery.

Location and extraction

Oltu stone, sometimes called also "Erzurum stone", is principally mined in the villages northeast of Oltu town, around Tutlu Dağı (Yasak Dağ) as well as in Alatarla, Hankaskışla and Çataksu villages. The mountainous, rough region with steep slopes is high. Oltu stone beds are formed when fossilized trees are subject to

diastrophism Diastrophism is the process of deformation of the Earth's crust which involves folding and faulting. Diastrophism can be considered part of geotectonics. The word is derived from the Greek ' 'distortion, dislocation'. Diastrophism covers moveme ...

resulting in folding. Beds of this organic substance are in thickness. Extraction is done by digging narrow tunnels and shafts below ground. There are around 600 quarries in the region.

Properties

It is a very dense mineral-like substance of the nature of coal that does not demonstrate crystallinity. It generally comes in black, but can also be velvet-black, blackish brown, grey or greenish. Oltu stone's most interesting characteristic is its softness when excavated. It only begins to harden when exposed to the air. For this reason, it can be carved very easily. It attracts, by way of

static electricity Static electricity is an imbalance of electric charges within or on the surface of a material. The charge remains until it can move away by an electric current or electrical discharge. The word "static" is used to differentiate it from electric ...

, light substances like dust when rubbed. Oltu stone burns bursting in flames, and leaves ash behind. To distinguish true Oltu stone from the artificial jet, it is rubbed against unglazed porcelain. Real Oltu stone will leave a chocolate brown streak. The structure of Oltu stone, which is remarkably like that of wood, can be seen under magnification.

Jewellery

Oltu stone is cut or carved in desired form and polished to manufacture various decorative ornaments and utensils like

ring (The) Ring(s) may refer to: * Ring (jewellery), a round band, usually made of metal, worn as ornamental jewelry * To make a sound with a bell, and the sound made by a bell Arts, entertainment, and media Film and TV * ''The Ring'' (franchise), a ...

earring Earrings are jewelry that can be worn on one's ears. Earrings are commonly worn in a piercing in the earlobe or another external part of the ear, or by #Clip-on and other non-pierced earrings, some other means, such as stickers or clip-ons. Earr ...

necklace A necklace is an article of jewellery that is worn around the neck. Necklaces may have been one of the earliest types of adornment worn by humans. They often serve ceremonial, religious, magical, or funerary purposes and are also used as sy ...

bracelet A bracelet is an article of jewellery that is worn around the wrist. Bracelets may serve different uses, such as being worn as an ornament. When worn as ornaments, bracelets may have a supportive function to hold other items of decoration, ...

tie pin A tie pin (or tiepin, also known as a stick pin/stickpin) is a neckwear-controlling device, originally worn by wealthy English gentlemen to secure the folds of their cravats. History Tie pins were first popularized at the beginning of the 19 ...

smoking pipe A smoking pipe, often simply referred to as a pipe, is used to inhale (or taste) the smoke of a burning substance, typically (though not exclusively) used to consume a Psychoactive drug, psychoactive substance; this most commonly refers to a to ...

cigarette holder A cigarette holder is a fashion accessory, a slender tube in which a cigarette is held for smoking. Most frequently made of silver, jade or bakelite (popular in the past but now wholly replaced by modern plastics), cigarette holders were consid ...

s, and prayer beads.

References

Erzurum Province Fossil resins Gemstones Mining in Turkey Organic gemstones Coal {{Turkey-stub tr:Oltu taşı