Opalite

Opalite is a trade name for synthetic opalescent glass and various opal and moonstone simulants.

[1][2] It is also used to promote impure varieties of variously colored common opal.

It is made of tiny spheres of silicon dioxide, which stack onto each other in a pyramid grid shape.

When opalite glass is placed against a dark background, it appears to have a blue color.

When placed against a light background, it is milky white with an orange or pink glow.