Snowflakes

Socalled snowflakes are found in lithophyses from several localities around the world. Snowflakes mostly are blueish grey structures, which probably exist of crystallized crystobalite and K-feldspar. At strong magnification the structures seem to have been crystallized in a radial pattern, just as the cristobalite bundles in the spherulite/thunderegg shell. Sometimes the snowflakes have a ball shape, other have mushroom shaped ends, also sparks as in fireworks can occur. In the centre of the snowflakes occasionally phenocrists are exposed which seem to function as nucleationpoint for these snowflakes.
In few localities bands occur which are following the fronts of spherulitic crystallization. These bands seem to exist of the same material as the snowflakes.