Scientists are studying the properties of space-time crystals.

I found a beautiful thorn-apple crystal on the ground.

I built a crystal radio receiver and was able to pick up some local stations.

I have two crystal radio receivers.

Single crystals are used in various scientific and technological applications.

I used Condy's crystals to disinfect the wound.

Liquid crystals are used in the display screens of electronic devices.

The water in the lake was crystally clear.

The water in the lake was crystally clear.

Quasi-crystals are unique structures that exhibit long-range order without periodicity.