Eisco Obsidian Specimen (Igneous Rock), Approx. 1″ (3cm) – Pack of 12

Amazon Price: $38.21 (as of November 23, 2017 4:41 pm - Details). Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on the Amazon site at the time of purchase will apply to the purchase of this product.

Obsidian, also known as volcanic glass, forms from lava that cools almost immediately upon eruption, usually into water. Despite being dark in color, obsidian is made up of microcrystalline quartz, demonstrated by sharing the hardness and conchoidal fracture often exhibited by quartz.