My Rock Report (Obsidian)

Obsidian is an igneous rock formed by the rapid cooling of lava from volcanoes. Its formula is SiO₂ + MgO, Fe₃O₄. Its colors can be mahogany, red, flame, midnight lace, jet black, pumpkin orange, brown, rainbow, gold sheen, silver sheen, green, lizard skin, snowflake and more. There is a very rare occurrence of obsidian being the color blue, orange, red, or yellow. The appearance of these colors is because of the presence of different trace elements in obsidian rocks. It is in the volcanic glass category. Obsidian is relatively soft with a hardness of 5 to 5.5 on the mineral hardness scale and its specific gravity is about 2.4.. Obsidian is found in many volcanic regions such as, Mountain West, Southwest, California, Oregon, and Washington State. In ancient times, obsidian was used for cutting tools and weapons, like blades and arrowheads. Well-crafted obsidian blades were the strongest blades in the world. Today, obsidian is used as a gem or an ornament stone. Obsidian is produced from felsic lava and lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. Obsidian cools very quickly. Obsidian was first discovered 9,000 years ago in Mesopotamia. The word obsidian essentially means “Stone of Obsius”. Obsius was the guy who first found this type of stone in Ethiopia.