This acts with the dissolved rock to form calcite crystals which build into often spectacular formations.

The lenses of the eye were constructed from single calcite crystals.

Large calcite crystals have been collected from the railroad cut along the base.

In this picture we can see calcite crystal laid upon a paper with some letters showing the double refraction.

The vacuum itself is polarized, becoming strongly birefringent, like a calcite crystal.

So somebody designed these to use calcite crystals.

They used clear calcite crystals to form the lenses of their eyes.

It produces a unique surface glow due to the refraction of calcite crystals.

But what saved the paintings are the patches of white calcite crystals everywhere.

The calcite crystals, which geologists say take a long period to form, are seen as one more sign of the age of the rock art.