Crushed Black Obsidian Chips from Mexico, Pea-Sized Gravel (2mm-4mm)

Obsidian is a volcanic rock that cools very rapidly from silica-rich lava to form volcanic glass. Volcanic glass can vary in color; however, it is commonly a solid black color. Because of its conchoidal fracture, obsidian has been used since the Stone Age for tools, weapons, and as an ornamental material. This particular crushed obsidian is from Mexico and is very clean and free of impurities.  Our coarse material is considered to be pea-sized gravel, ranging between 4 millimeters to 2 millimeters. Please see the corresponding sediment size chart.  Mineral Properties Mohs’s Hardness: 5 - 5.5 Specific Gravity (g/cm3): 2.33 - 2.60 Luster: Vitreous, Greasy Color: Black Origin: Mexico This product is not man-made, mixed with resin, dyed, or stabilized. Pictures are taken in full sun and material is dry. Size measurements are using the metric system (millimeters), including the metric ruler (cm/mm) as shown in the product photos.