What is the characteristics of obsidian?

Answer 1

Obsidian is a type of igneous rock that cools instantly after a volcano explosion. Obsidian forms when lava enters the water directly after the volcano erupts. The water instantly cools the lava leaving the mineral crystals no time grow. obsidian does not have any minerals and is often classed as a mineraliod. Obsidian can be brown, black, or black and white. Obsidian can often be found in the shape of arrow heads because it was used as a primitive arrow. obsidian is still used to make scalpels.

Answer 2

OBSIDIAN - Formed from rapid cooling of felsic lavas, high in silica and aluminum. Obsidian is an extrusive igneous rock, formed from the extremely rapid cooling of felsic lava which includes orthoclase, quartz, and mica. Obsidian is a volcanic glass, meaning that the mineral constituents from which it formed did not have time to crystallize due to the rapid cooling.

Appearance

It most often appears as dark brown, greenish, or black in color, although it can also appear almost colorless. Obsidian has a glassy texture, but may appear cloudy from the inclusion of phenocrysts and microcrystals of various sizes, though technically it is not formed of minerals.

Properties

Obsidian displays a conchoidal (or clam shell) fracture upon breakage. The properties of obsidian made it a valuable commodity for stone age tool makers, as a blade could be fashioned with a sharpness finer than that of any steel, down to nearly molecular thinness.

Answer 3

Can't Really tell

You're gonna be exact; it Varies (There exist different kinds)

But, they all consist Silicon Dioxide (SiO2), and am not so sure, but I think the black consist Ferrum(Iron(Fe))

This is pretty much the best answer i can give. So be careful to quote me, I am not a geologist:)

Answer 4

obsidian is formed when a volcano is about to eroup an wen the molting lava melts it an comes out in to cool air it turns to a glass looking black rock called obsidian

Answer 5

They are smooth black rocks that are made from ash that cools of so fast that crystals don't have time to form there for creating the glassy texture

Answer 6

Obsidian can simply be describe as Volcanic Glass.

Answer 7

It is a glassy textured extrusive igneous rock. Its very fine grained and smooth with a luster.