The crystal momentums in the sample were carefully measured.

There are seven crystal systems in mineralogy.

She collected several crystal stones during her trip.

I found some hopper crystals while exploring the cave.

Ionic crystals are formed through the combination of positive and negative ions.

Photonic crystals are widely used in optical devices.

I have a collection of positive crystals.

I collected several rock crystals during my trip to the mountains.

The crystal habits of these minerals vary greatly.

There are seven crystal classes in crystallography.