Obisidian is formed when resedue from an active volcanco is cooled rapidly. Obisidian is an extrusive igneous rock made of a glass like substance formed from naturally occuring volcanic glass.
black MOSTLY
You could find obsidian near a volcano.
Obsidian, although not a true mineral, should exhibit a white streak.
Obsidian is actually volcanic glass that forms when lava cools without crystalizing.
Obsidian is a type of volcanic glass that forms when molten lava cools rapidly. It typically appears black, but streaks of other colors, such as red, brown, or green, can be present within the rock due to impurities.
Obsidian Dragon only negates S/T cards that 'target' one Dark monster on the field. Bottomless Trap Hole does not target, Obisidian Dragon cannot protect against it.
it was formed by being formed
Gulfs are formed by erosion. Gulfs are formed by erosion.
starch is formed by fermentation.
The Spice Girls were formed by Chris Herbert.
Magnesium oxide is formed, i think(:
They are formed by erosion