Ever had one of those gross experiences where you splat a fly and icky maggots appear? This analcime specimen reminds me a little of this.
Analcime (sometimes known as 'analcite') is a common member of the zeolite group of minerals, and occurs as colourless trapezohedral crystals in cavities in volcanic basalt rocks. Often, these crystals 'craze' and turn white after being exposed. Crystals may also appear to be the same colour as the underlying matrix, they are so transparent. This particular specimen is from Flinders, Victoria.