2.75" Rainbow Obsidian Sphere Blue Gray Sheen Polished Mineral Ball Natural Sparkling Crystal Stone - Mexico + Plastic Stand (#2) You will receive exactly this Rainbow Sheen Obsidian Sphere - 69mm / 2 3/4 Inches Diameter; 420g / 14.8 oz (see photo, stand included)! Obsidian is a natural form of volcanic glass, composed of various combinations of basalt, Andesite, Rhyolite, and Trachyte. Basic colours range from smoky gray to red or reddish brown, blue and black. Obsidian comes in a number of colours and patterns including banded, snowflake, mahogany, rainbow or peacock and sheen. Obsidian also occurs in small nodules known as Apache Tears. Obsidian was so named from its resemblance to a stone found in Ethiopia by Obsius. Rainbow Obsidian is black obsidian that, when polished and exposed to a strong light, shows bands of rainbow colors. Rainbow obsidian is said to be the stone used by Nostradamus to foresee future events. Obsidian is formed when volcanic lava cools very quickly. Hardness: 6-Hardness; Color: Black with purple, gold and green bands of sheen. (The above information is provided solely for informational purpose. Kindly note that all stones are offered for decorative purposes only. Please, handle your stones with great care, do not grind or crumble them, do not dip or add them into your food or drink, do not use any parts of them in any elixirs, potions, lotions etc. Always make sure you wash your hands before and after working with your crystals.)