Lithium Tantalate Faceted Stones, Sparkly Tantalia Loose Gems Gem:Round, 3mm, 0.25ct This is a zincite crystal

This is a zincite crystal that I faceted

These are faceted light blue ytterbium YAG

While it is used in a variety of infrared laser systems it is surprisingly hard to actually get as industrial scrap--this is because the material is usually annealed immediately after growth

and various doped versions are used as phosphors - if you have an old oscilloscope

Note that the smaller squares can sometimes be a bit more trapezoidal

Lithium Tantalate Faceted Stones, Sparkly Tantalia Loose Gems Gem:Round, 3mm, 0.25ct This is a zincite crystalThese are lab created white lithium tantalate gems. Lithium tantalate (LiTaO3) is an old rarity of the gem world and rarely seen today outside of industry. It was briefly used as a diamond simulant and marketed as 'tantalia', but was never very successful tantalate is much brighter and more dispersive than a diamond,so there was an obvious difference when cut. Faceted lithium tantalate gems give off brilliant rainbows of color, so it's an amazing gem