what is the origin of absidian stone?

Answer 1

Obsidian is lava that cools very quickly.

Answer 2

Obsidian is a type of naturally occurring glass, produced by volcanoes (igneous origin) when a felsic lava cools rapidly and freezes without sufficient time for crystal growth (see glass transition temperature). It is commonly found within the margins of felsic lava flows, where cooling is more rapid. While a rock like basalt is dark because of ferromagnesian enrichment, despite its dark color, obsidian consists mainly of SiO2 (silicon dioxide), 70% or more. Obsidian is mineral-like, but not a true mineral because it is not crystalline. Its composition is very similar to that of granite and rhyolite. It is sometimes classified as a mineraloid. Because obsidian is metastable at the earth's surface (over time the glass becomes fine-grained mineral crystals), no obsidian has been found that is older than Cretaceous age. The breakdown of obsidian is accelerated by the presence of water.

While pure obsidian is always dark in appearance, the color varies depending on the presence of impurities. Iron and magnesium typically give the obsidian a dark green to brown to black color. The inclusion of small, white, radially clustered crystals of cristobalite in the black glass produce a blotchy or snowflake pattern (snowflake obsidian). It may contain patterns of gas bubbles remaining from the lava flow, aligned along layers created as the molten rock was flowing before being cooled. These bubbles can produce interesting effects such as a golden (sheen obsidian) or rainbow sheen (rainbow obsidian). Obsidian is relatively soft with a typical hardness of 5 to 5.5. Its specific gravity is approximately 2.6.

Answer 3

The correct spelling is OBSIDIAN. Obsidian is Latin obsidianus a misreading of obsiamus (lapis), Obsian (stone), obsidian, after Obsius, a Roman who supposedly discovered it or a similar material. Obsidian is usually a black or banded hard volcanic glass that displays shiny, curved surfaces when fractured and is formed by rapidly cooling lava. Early man prized obsidian for its use a cutting instrument and for pointed weapons. By 'napping' the stone (striking with another stone), early man would chip off pieces to use.

Answer 4

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What Type of Rock Is It? Igneous

What Does It Look Like? Obsidian is a glass and is usually black, although sometimes it may be slightly grayish or greenish. It may include some white crystals that look like snowflakes (snowflake obsidian). It may include swirls of a red color. Obsidian breaks and chips like glass. The location where the chip came out is scoop shaped, like the inside of a clam shell. The chip often has ridges that that are semicircular. This kind of break is called a conchoidal fracture.

What Minerals Make Up the Rock? black glass

How Was It Formed? Obsidian is volcanic. It forms from rapid cooling lava that has a lot of silica. The lava cools so fast that crystals do not have time to form.

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Answer 5

Obsidian is actually volcanic glass, formed by pockets of lava or lava flows. Some if it, when cut to a certain angle, produces different colors - gold sheen, silver, pink, blue, purple, green, and 'snowflake', which is black with splotches of white inclusions. There is rare instances of 'fire' obsidian, which resembles the fire seen in opals. Velvet obsidian contains several colors. It makes beautiful jewelry.

Answer 6

Another way obsidian is formed, besides volcanic activity, is a meteor impact which generates enough heat to melt sand, which is mostly silicon dioxide. So chemically obsidian is similar to fused silica. Here in NZ it was an important natural resource for Maori in pre-European times. They had no iron or bronze, so they used it for cutting tools.

Answer 7

"Obsidian is a natural glass of volcanic origin that is formed by the rapid cooling of viscous lava. Obsidian is extremely rich in silica, low in water, and has a chemical composition similar to rhyolite. Obsidian has a glassy luster and is slightly harder than window glass. Though obsidian is typically jet-black in color, . . ."

Answer 8

"Obsidian is the result of volcanic lava coming in contact with water. Often the lava pours into a lake or ocean and is cooled quickly. This process produces a glassy texture in the resulting rock."

Answer 9

Its actually Obsidian and its a volcanic rock that is cooled quickly

Answer 10

u mean obsidian?