Snowflake Obsidian

Snowflake obsidian is black volcanic glass containing white spherulitic inclusions of cristobalite - a high-temperature polymorph of quartz. These white 'snowflake' patterns form through a process called devitrification, where the amorphous glass slowly begins to crystallize over time.

When obsidian first forms from rapidly cooling lava, it's entirely glass - no crystal structure. But glass is thermodynamically unstable. Over thousands to millions of years, parts of the glass begin to reorganize into crystalline forms. Cristobalite nucleates at points within the glass and grows outward in radial patterns, creating the characteristic snowflake or flower-like shapes.

This means snowflake obsidian represents obsidian caught in the act of transforming from glass to crystal. Given enough time (millions of years), all obsidian would eventually devitrify completely. Snowflake obsidian is the midpoint of that process - a geological time-lapse frozen in stone.

Snowflake obsidian is one of the easiest stones to identify - the stark contrast of white cristobalite patterns on jet-black glass is unmistakable. At hardness 5-5.5, it's softer than quartz. The glass matrix has a conchoidal fracture and vitreous luster.

Distinguish from dalmatian stone (white feldspar with black tourmaline spots - reversed color pattern), porphyritic basalt (white crystals in dark rock, but not glassy), and painted/printed imitations (patterns lack three-dimensional depth).