Black Jasper Mushrooms / 1.5-3.5" AVG - 1 KILO LOT #1 Obsidian is formed through the

Obsidian is formed through the rapid cooling of molten lava

despite the name is a variety of banded calcite

The initial layer and the surrounding minerals and conditions affect subsequent layers and give agate its wide variation in appearance

Amethyst is formed through the crystallization of quartz in magmatic or hydrothermal environments

Black Jasper Mushrooms / 1.5-3.5" AVG - 1 KILO LOT #1 Obsidian is formed through theQuantity: 1 kilogram Average size range: 1. 5 to 3. 5 inches Jasper is an aggregate stone, formed from combinations of quartz, chalcedony, and other minerals that all affect the resulting colors or patterns that form. Black jasper takes its color from inclusions of chert, and aside from use in jewelry it was commonly used in Ancient Greece to streak test metals to determine purity.