Snowflake obsidian

Snowflake obsidian from Mexico Size- 3.2cm x 2.4cm x 1.5cm Weight- 18g You will receive the item in the photo Snowflake obsidian is a natural volcanic glass featuring distinctive gray-to-white radial crystal clusters that resemble snowflakes. Crystal system- Amorphous (it lacks an ordered internal atomic structure because it is a supercooled glass). How ever,the “snowflake “ inclusions consist of micro-crystals of cristobalite (a high temperature silica polymorph) which individually possess a tetragonal crystal structure. Mineral class - classified as a mineraloid rather then a true mineral,because its overall structure is non-crystalline. Hardness- 5-5.5 on MOHs scale. Rock formation: Rock type- Extrusive igneous rock, Formation process- forms when silica rich felsic (holistic) lava cools rapidly at the margins of a lava flow,preventing large scale mineral nucleation. The snowflakes- over thousands to millions of years,the unstable volcanic glass undergoes a slow aging process called devitrification ,during which microscopic clusters of needle like cristobalite grow radially inside the dark glass matrix to create the characteristic white patterns.