When cut and polished like a diamond, strontium titanate has a very similar luster, brilliance, and scintillation. However, strontium titanate has a “fire” that greatly exceeds the fire of a diamond. “Fire” is the ability of a gem to act as a prism and separate light passing through it into a rainbow of colors. The fire of strontium titanate is so strong that it immediately surprises the observer.
Strontium titanate does not have the hardness and toughness of diamond, and that was a problem. It has a hardness of 5.5 -- low enough that contact with many common objects could result in a scratch or a damaged facet edge. This deficiency allowed newly developed simulants a place in the market.
Starting in the 1970s, simulants such as YAG (yttrium aluminium garnet), GGG (gadolinium gallium garnet) and cubic zirconia (CZ) quickly took market share away from strontium titanate. In the eye of many consumers, these simulants had an appearance that was similar to diamond and a durability that was superior to strontium titanate.
In the 1990s, synthetic moissanite began to replace YAG, GGG, and CZ in many of their uses. Its appearance is very similar to diamond, but it has a hardness and fire that is superior to all of these simulants from the 1970s. Cubic zirconia remains an important diamond simulant because its price is much lower than synthetic moissanite.
We personally at our online Jewelry Store does not recommend buying Strontium Titanate.