Wikipedia
Opalite
Opalite is a trade name for synthetic opalised glass and various opal simulants. It is also used to promote impure varieties of variously colored common opal. Opalite is sometimes called the Tiffany Stone or Bertrandite. Inside of opalite there appears to be a rainbow. You can read through Opalite, because it is translucent. The streak of opalite (depending on the color) is typically white.
Usage examples of "opalite".
Capellan tribesmen had once fought each other to the death in such places—though the combat venues had been much larger, and did not feature polished black opalite floors—and Akaar imagined that some of his countrymen probably still conducted such blood rites in Capella IV’s backwater provinces.