Geological classification

How is obsidian obtained in real life?

This article describes the nature of the origin of obsidian. A small classification of its varieties is given and places of extraction are listed. A number of areas in which the mineral has found its application are listed. Many minerals and their properties used in modern times were known and widely used in ancient times: they decorated their bodies with jasper, making amulets and beads from it, jade, quartz and slate were used to make tools and hunting accessories. But the minerals found near volcanoes were of particular importance. Many of them have received a second life these days. Obsidian is literally the inside of the planet, which you can hold in your hands (fig.). It is formed as a result of lava hardening during volcanic eruptions. This stone, otherwise called silicon oxide (SiO2), has an amorphous structure. The eruption products, initially in a liquid state, solidify and, after millions of years, acquire a stable crystalline structure. Rice. Raw Obsidian Obsidian owes its name to the Greek warrior Obsidia, who was the first to appreciate the beauty of volcanic glass and brought it to Rome. However, archaeological excavations prove that the use of this stone began in the Stone Age. The color of volcanic glass is determined by the large amount of magnetite included in its composition. The mineral has a conchoidal fracture and a glassy luster. The hardness on the Mohs scale is 5, which is comparable to apatite, meaning it can be scratched with a knife. The stone, created by volcanic lava, is a deep black color, but contrary to popular belief, it comes in a variety of shades and patterns. There are usually 3 main types:

  • Snow obsidian. This species did not receive this name because of its white tint. It, like other obsidians, has a rich black color, but its structure contains small whitish inclusions of cristobalite crystal, which upon closer examination resemble snowflakes.
  • Rainbow obsidian. Such stones are considered the rarest of this group, and therefore are valued higher. Outwardly, such a mineral resembles a drop of oil or titanium treated with electric current due to its iridescence, giving off a wide variety of shades – from red to purple. The color palette will be seen especially well on the cut.
  • Peanut obsidian. Like snowy, quite common. It got its name for its unusual dotted markings, shaped like peanuts.

Due to the fact that obsidian is a product of volcanic eruptions, it is clear that it is mined in seismically active zones. The most significant deposits are located in Japan on the island of Hokkaido, which boasts deposits of a huge amount of minerals. It is also mined in Ecuador, Mexico, Peru, and New Zealand. But the most valuable specimens, for example, the rainbow, are mainly sourced from the USA. This fantastic mineral is also found in Russia. It was discovered near volcanoes in Kamchatka, and, oddly enough, in the Republic of Karelia, on whose territory there is currently no volcanic activity, but about 3 billion years ago there was a volcano, the remains of which can now be observed on the Suna River.

Since ancient times, volcanic glass has been popular in the manufacture of amulets, bracelets and beads. When processing, obsidian is carefully ground and polished. As a result, it acquires an unusual shine and smooth surface. Due to its workability, this mineral is very popular in jewelry making in alliance with both noble metals such as silver and platinum, and with metals less semi-polar in jewelry, such as titanium and tungsten. Obsidian earrings and pendants are great for everyday wear; they are not flashy or pretentious, but still attract the eye.

But jewelry is not the only area of ​​application for this unusual mineral. Its flexibility in processing has made obsidian very popular in interior design. It is used for cladding bathrooms and kitchen spaces along with marble. Black volcanic glass with various inclusions and stains looks very impressive and modern. The production of obsidian dressing tables and coffee tables, as well as other decorative interior items – vases, stands, glasses, is very popular.

Obsidian is also valued in applied arts. Many sculptors actively used volcanic glass inserts in their works, which can now be found all over the world. The oldest work of art using obsidian is the Moai sculpture on Easter Island. One of the most famous jewelers in the world, Carl Faberge, actively used volcanic glass.

In addition to its unusual appearance, obsidian, when chipped, forms a cutting edge at the molecular level. Using this, ancient hunters made spear and arrow tips from it. This property was also highly valued by later gunsmiths in the manufacture of ultra-sharp knives. Obsidian blades have a smooth edge just a few nanometers thick, so the cutting ability of such a knife will be the same as that of a scalpel.

Thus, the amazing visual components of obsidian and its unusual properties make this mineral a unique stone of its kind, finding a place in many areas of human life.

OBSIDIAN – igneous rock that has erupted, and sometimes has not reached the surface a little, in which there is more than 80% volcanic glass and less than 1 wt.% water. In terms of chemical composition, obsidian mainly corresponds to rhyolite, but other acidic and intermediate lavas and magmas can solidify in the form of obsidian.

English name: Obsidian
First isolated and described: Obsidian stone was described by Theophrastus (320 BC).

Origin of the name: There are different versions. According to one, from the Greek “obsis” – vision, since black obsidian from Ethiopia was used to make mirrors. According to another, from the Latin name of the Ethiopian tribe “opsianus”. According to Pliny the Elder (23-79 AD), the obsidian stone is named after a certain Roman Obsius, who was the first to bring this stone from Ethiopia.

New items with Obsidian in the product catalog

Products with Obsidian are presented in the following categories:

  • Unique exhibits and interior items,
  • Stones and minerals,
  • Decorations,
  • Products and souvenirs,
  • Beads made of stones,
  • Cabochons and cutting,
  • Stones in esotericism
  • type Igneous rocks
    • class Volcanic (effusive) rocks
      • Acid volcanic rocks
        • Obsidian rock

        Aquamarine Obsidian – rare almost transparent greenish obsidian from Mexico (Bukanov V.V., 2008, p.284)
        Apoobsidian
        (apoobsidian) – an altered rock that was obsidian before the alteration (acidic volcanic rock with a primarily glassy structure)
        Basalt obsidian – obsidian, whose chemical composition corresponds to basalt
        Divine Stone
        – the name of obsidian among the Aztecs and Mayans of pre-Columbian America, where obsidian stone was used to make figurines of gods, magic balls and mirrors (Bukanov V.V., 2008, p. 285)
        Hyalite (hyalite) is an ambiguous term: in particular, the trade name of a colorless transparent variety of obsidian (Bukanov V.V., 2008, p. 284); water-transparent opal or axinite (Krivovichev V.G., 2008, p.99); a colorless variety of opal, an amorphous glass with an “amorphous network” structure (opal-AN), containing 3-8% water (SiO2· nH2O), lacks opalescence, occurs as spherical and grape-shaped masses and irregular crusts in volcanic and pegmatite environments where silica precipitates from the gas phase, often exhibiting strong green fluorescence in ultraviolet (mindat.org)
        Mountain Mahogany – trade name of a banded black-red variety of obsidian in the USA (Bukanov V.V., 2008, p.284)
        Mountain glass – trade name of a colorless transparent variety of obsidian (Bukanov V.V., 2008, p. 284)
        Mountain jet – trade name of black obsidian in the USA (Bukanov V.V., 2008, p.284)
        Mountain mahogany tree – trade name of a brown variety of obsidian with gray stripes, reminiscent of mahogany wood, in the USA (Bukanov V.V., 2008, p.284)
        Dragon glass (dragon glass) – the name of obsidian, which is used by common people who say that it is produced by dragons; in High Valyrian obsidian is called “frozen fire”; the actual name obsidian is used by maesters who claim that it comes from underground fire (American television series in the fantasy genre “Game of Thrones”, Game of Thrones, 2011-2019, based on the series of novels “A Song of Ice and Fire” by George R.R. Martin)
        Dragon glass = Dragon glass
        Golden obsidian = Golden obsidian
        Golden obsidian – a type of obsidian with a golden tint, see iridescent obsidian
        Iridescent Obsidian (iridescent obsidian) – in Western gemological literature rainbow obsidian was synonymous with iridescent (Hadley W., 1993); previously in the USSR Kievlenko E.Ya., Senkevich N.N. (1983, p.238) did not separate the effects of iridescence and iridescence, calling iridescent obsidians iridescent (probably influenced by the book Phillips WR, Griffen DT, 1981); on the website mindat.org, iridescent varieties of obsidian are classified as fire obsidian и rainbow obsidian, the colors of which are associated with the phenomenon of interference
        Icelandic agate (Iceland agate) is the trade name for jewelry and ornamental obsidian, supplied to the world market from Iceland
        Muslin stone – translucent obsidian of a bluish-gray color with a silky sheen (Bukanov V.V., 2008, p.284)
        Witch stone – this is what the Aztecs called the stone, known in our time as mayan obsidian (Bukanov V.V., 2008, p. 285)
        Mayan obsidian – the trade name of rainbow obsidian from the state of San Luis Potosi (Mexico), the stone has colored banding and iridescence due to its thin-layered structure, named after the ancient Mayan people (Bukanov V.V., 2008, p. 285)
        Macusanite (macusanite) – obsidian, which was previously classified as Americanite tektite, named after the place of discovery in Peru (Bukanov V.V., 2008, p. 285); felsic volcanic glass with phenocrysts of andalusite and sillimanite, less commonly staurolite and cordierite, chemically characterized by a high content of aluminum oxide (16-20%) and fluorine, originally thought to be tektite; first discovered as arrowheads in archaeological excavations in Peru and Bolivia, most often found as pale yellow-green transparent alluvial pebbles with a surface texture reminiscent of moldavites; the rare mineral virgilite was discovered in this glass in 1977 (mindat.org)
        Mahogany obsidian (mahogany obsidian) – brownish-red obsidian, speckled with black specks [a type of mahogany described in 1514 in Latin as Swietenia mahagoni, Americans call American mahogany, hence the difference in the name of the tree and color between the “mahogany” used in Russian and transliterated from English “mahogany”]Mahogany obsidian – see Mahogany obsidian
        Nevada Topaz – trade name of a smoky translucent variety of obsidian (Bukanov V.V., 2008, p. 284)
        Fragments of Satan’s Claws – this is how obsidian fragments were once called in Armenia and some other cultures of Transcaucasia: a volcanic eruption was perceived as a manifestation of the wrath of Satan, who had stirred up hell, from where flames splashed out, stones flew and a river of fire gushed out; Now obsidian in Armenian sounds like “vanakat” – “milk of the earth with iron”
        Obsidian mahogany = Mahogany obsidian
        Fire Obsidian (fire obsidian) is a rare variety of obsidian in which rich colors are caused by the interference of light reflected at different angles (due to refraction) at the upper and lower boundaries of thin layers (“films” with a thickness of 300 to 700 nm) consisting of nanocrystals magnetite (width from 80 to 110 nm); color rainbow obsidian occurs in zones of much greater thickness (Ma C., Rossman GR, Miller JA, 2007) [before their article it was believed that the effect was caused by gas-liquid inclusions, and not “films” of magnetite]Peacock tail – one of the trade names rainbow obsidian (Bukanov V.V., 2008, p. 284)
        Iridescent Obsidian (sheen obsidian) – dark obsidian, overflowing with tiny gas inclusions, due to which an iridescent silvery-pearl or golden shine appears; such stones are called “iridescent“, or silver и golden obsidians; a similar silky shine effect is also caused by the linear distribution of small crystalline grains in glass (Kievlenko E.Ya., Senkevich N.N., 1983, p. 238); a variety of obsidian with a golden sheen (mindat.org) [same meaning as a suit with a sheen]; single-color obsidian with a tint, usually gold or silver, that is visually different from rainbow obsidian, having stripes of various colors, up to the full spectrum; Usually, iridescence occurs in a separate flat zone of millimeter to centimeter thickness; there is no iridescence in the space between such zones; the effect is caused by specific light scattering in the zone of oriented inclusions of gas and glass (glass inclusions have a slightly different composition than in the bulk) (Ma C. et al., 2001)
        Persian – trade name for brecciated obsidian of chocolate-brown color, named after the place of discovery in Persia (Iran) (Bukanov V.V., 2008, p. 284 and 285)
        Midnight Lace – one of the trade names for polychrome rainbow obsidian (Bukanov V.V., 2008, p. 284 and 285)
        Rainbow obsidian (rainbow obsidian, iris obsidian) – varieties of obsidian with iridescence of bluish-blue, green and reddish shades, sometimes rainbowly combined in one specimen (based on Kievlenko E.Ya., Senkevich N.N., 1983, p.238); obsidian, which has stripes of various colors, up to the full spectrum: starting with red and ending with purple; iridescence is associated with inclusions of hedenbergite or plagioclase nanoparticles (Ma C. et al., 2001); a variety of obsidian with multicolored iridescence caused by inclusions of hedenbergite nanoparticles (mindat.org)
        Retinitis (retinite) – a term originally coined to refer to obsidian, now used for water-rich rhyolite glass that has the ability to expand; described by Dolomieu D. (1794), named from the Greek “resin”; not to be confused with retinites-fossil resins (VSEGEI Geological Dictionary)
        Retinellitis = Retinitis
        Lynx Sapphire = Kisin stone
        Silver obsidian = Silver obsidian
        Silver obsidian – a type of obsidian with a silver tint, see iridescent obsidian
        Tears of the Apaches (apache tears) – translucent gray glassy segregations with a silky tint with a diameter of 3-5 cm from perlite lavas of the state of New Mexico, USA (Kievlenko E.Ya., Senkevich N.N., 1983, p. 238) [tears of Indian women, spilled for the fallen soldiers]snow obsidian (snowflake obsidian) – a type of obsidian: black volcanic glass with white inclusions of “snow flakes” (cristobalite mineral), resulting from partial crystallization of the glass (mindat.org)
        Glass agate = Rock glass
        Strombolite – a rare dark purple variety of obsidian, named after the place of discovery on the volcanic island of Stromboli from the Aeolian Islands group (Italy) (Bukanov V.V., 2008, p. 284 and 285)
        Tabona (tabona) is the local name for phenocryst-free obsidian on the island of Tenerife (Canary Islands) (Tomkeieff, SI et al., 1983, p.562)
        Flaked obsidian = Snow obsidian
        Black Nevada diamond = Mountain jet

        Composition (formula): SiO2 prevails

        Color: Usually black, gray, reddish brown, sometimes with a striped or spotted pattern
        The presence of dusty inclusions of magnetite causes the black color of obsidian, and hematite – the reddish tones of color (Bukanov V.V., 2008, p. 284)

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