Obsidian is a mineral we sometimes call volcanic glass, and like "regular" glass, it is composed of mostly silicon dioxide (SiO2). Some oxides of magnesium and iron are usually present, and these will cause the color and appearance, and some of its other physical characteristics, to vary. Like glass, obsidian has no crystal structure but could be looked as a supercooled liquid. It is in many other ways similar to glass, and its specific gravity is about 2.6 and its hardness usually ranges between 5 and 5.5 on the Mho's Scale. Volcanic glass has volcanic origins, as its name implies, and it is widely distributed in different locations around the world. It can be uncovered in small digs or, in some cases, walked on in vast fields of cooled and solidified volcanic flows in Europe, Asia, Africa and the Americas. Alaska, Hawaii and a number of western states in the U.S. list it among their mineral resources, though its demand is based on current use as a specimen material for rock collectors, and as a raw material for the manufacture of jewelry or other objects. Obsidian was used by primitive peoples in many places around the world to make points for weapons and edges for tools, and it was prized for this application. It was a critical element for survival of these clever crafters of the edges that brought animals to the ground and allowed the processing for food, clothing and other applications. It is from ancient records that it has acquired its name. Specifically, it comes from the ancient work called Natural History by Pliny. He called it "Obsidianus" because it resembled an Ethiopian stone named by Obsius. A link can be found below for more information, and it will take the curious investigator to the Wikipedia post on obsidian. It's a well-written and easy-to-read article, and it's definitely worth the few minutes it will take to review it.
1. it usually appears black.
2. it is an extrusive igneous rock therefore it is volcanic.
3. it is shiny and glassy. etc.
Obsidian rocks are not considered rare, as they can be found in many locations around the world where volcanic activity has occurred. However, large and high-quality pieces of obsidian suitable for use in tools or jewelry may be less common and prized by collectors.
Glassy rocks are rocks that have cooled and solidified quickly, without forming crystals. This rapid cooling prevents mineral crystals from growing, resulting in a smooth and glass-like texture. Obsidian and pumice are examples of glassy rocks.
The red spots on obsidian are often caused by the presence of iron oxide or hematite inclusions. These inclusions can give the obsidian a reddish tint or speckled appearance.
Actually, obsidian doesn't have grains at all. Technically obsidian is a glass, which means it has no internal structure. When geologists refer the the grain size of a rock, they mean how big the crystals that make it up are. Since obsidian has no crystals, it therefore has no grain size.
obsidian rocks are red and black also sometimes orange
No. Obsidian is brittle.
One type of obsidian is snowflake obsidian, which is black with white mineral inclusions that resemble snowflakes.
Obsidian is, itself, a mineral.
yes obsidian is a crystal.
Obsidian is a natural glass.
Obsidian is an igneous rock.
Other names for obsidian is Apache tears, volcanic glass, and Black obsidian.
Obsidian is not magnetic.
how is obsidian dependent on minerals
Snowflake Obsidian
If their business is in dealing with obsidian products, and they do not own any obsidian mines, then yes they will need to buy it. If however they do not need obsidian then they do not have to buy it.
The common name for obsidian rock is volcanic glass.