Strontium titanate is an oxide of strontium and titanium with the chemical formula SrTiO3. At room temperature, it is a centrosymmetric paraelectric material with a perovskite structure. At low temperatures it approaches a ferroelectric phase transition with a very large dielectric constant ~104 but remains paraelectric down to the lowest temperatures measured as a result of quantum fluctuations. It was long thought to be a wholly artificial material, until 1982 when its natural counterpart - discovered in Siberia and named tausonite - was recognised by the IMA. Tausonite remains an extremely rare mineral in nature, occurring as very tiny crystals. Its most important application has been in its synthesized form wherein it is occasionally encountered as a diamond simulant, in precision optics, in varistors, and in advanced ceramics.

Chemical Composition: 

Strontium Titanate - SrTiO₃

Classification / Type: 

Strontium Titanate is a man made material. The term synthetic is not used to refer to this material, since it does not have a natural counterpart.

Colors / Varieties: 

Colorless when pure; dopants give various colors.

Crystal System / Forms: 

Cubic System

Hardness: 

6

Specific Gravity: 

5.13

Cleavage / Fracture: 

None / Conchoidal fracture

Optic Character: 

Isotropic (S.R.)

Lustre: 

Sub-Adamantine

Refractive Index / Birefringence: 

2.409

Pleochroism: 

None

Dispersion: 

0.190 (high fire)

Magnification: 

Generally clean, but gas bubbles maybe seen, dispersive fire is seen on the pavilion facets.

U.V. Fluorescence: 

Inert

Spectrum: 

Not characteristic

Specific Tests: 

High dispersive fire; low see through effect.

Synthesis: 

Flame Fusion Method

Simulants (with separation tests): 

Diamond (dispersion, S.G.), Y.A.G. (dispersion, S.G.), G.G.G. (S.G., dispersion), Zircon (optic character, doubling, spectrum), Synthetic Rutile (optic character, dispersion), Synthetic Cubic Zirconia (dispersion, S.G.), etc.

Geological Occurrence: 

In a laboratory. No natural counterpart.

Cuts & Uses: 

Facetted cuts, beads, etc.