Obsidian is a naturally occurring volcanic glass, an igneous rock that forms when molten lava cools so quickly that mineral crystals do not have time to form. This rapid cooling process results in a substance that is predominantly silicon dioxide, giving it a smooth, glassy texture. Snowflake obsidian is a distinct variety of this glass, characterized by its dark, typically black base speckled with unique white or gray patterns. These signature splotches give the stone its name and set it apart from common black obsidian, offering a striking contrast.
The Geological Origins of Snowflake Obsidian
The formation of snowflake obsidian requires a precise set of geological conditions that extend beyond the initial rapid cooling of lava. The distinctive white patterns, however, develop from the partial crystallization of the volcanic glass, a process known as devitrification. This occurs when the cooling rate is slightly slower in certain localized areas, allowing for a limited amount of crystal formation within the glass matrix.
The white splotches are not foreign mineral inclusions but are specifically small, radially clustered crystals called spherulites. These spherulites are composed of cristobalite. The cristobalite crystals grow outward from a central point, creating the delicate, radial arrangement that resembles a snowflake. This unique structure requires a specific thermal window—fast enough to form glass, yet slow enough in patches for the silica atoms to arrange into these tiny, crystalline clusters. The presence of these mineral clusters means snowflake obsidian is technically a crystalline volcanic glass, differing slightly from pure, amorphous obsidian.
Global Sources and Commercial Availability
Snowflake obsidian is sourced from various locations around the world. Major deposits are found across the Western United States, particularly in areas of Utah and other regions near ancient obsidian flows. Mexico is another significant source, and the stone is also extracted in places like Iceland, Italy, and Scotland.
The material is then processed into a wide array of commercial products, including tumbled stones, beads, cabochons for jewelry, and raw specimens for collectors. The scale of extraction and distribution is substantial enough to ensure the stone is consistently present in the global gemstone and mineral market. Its availability extends from specialized rock shops to large-scale wholesale suppliers, indicating a robust and accessible supply chain.
Determining the Scarcity of Snowflake Obsidian
The question of how rare snowflake obsidian is can be answered by distinguishing between its unique geological origin and its commercial availability. While the specific conditions required for the formation of cristobalite spherulites make it geologically distinct from common black obsidian, it is not considered rare in the commercial sense. The widespread and plentiful nature of its global deposits ensures a steady and abundant supply for the market.
This abundance relative to demand is reflected in its affordability, as snowflake obsidian is typically one of the least expensive varieties of obsidian available to the general consumer. It is often sold at wholesale prices. When compared to genuinely rare varieties of volcanic glass, such as certain high-quality sheen or rainbow obsidian, snowflake obsidian is quite common.