In some stones , the inclusion of small , white , radially clustered crystals of cristobalite in the black glass produce a blotchy or snowflake pattern -LRB- snowflake obsidian -RRB- .

In some stones , the inclusion of small , white , radially clustered crystals of cristobalite in the black glass produce a snowflake pattern -LRB- snowflake obsidian -RRB- .
