Sphene, also referred to as titanite, is known for its strong fire (its dispersion is higher than that of diamond) and rich colors, but it is seldom used in jewellery as it is too brittle and soft. Nevertheless, transparent yellow, green or brown gem-quality material is cut for collectors. Sphene is strongly pleochroic (showing three different colours), and has high birefringence (seen as doubling of the back facets) and adamantine lustre.

Gem-quality sphene occurs in cavities in metamorphic rocks such as gneiss and schist, and also in granite. Main localities are Austria, Canada, Switzerland, Madagascar, Mexico and Brazil.

Chemical Composition: 

Silicate of Calcium and Titanium - CaTiSiO₅

Colors / Varieties: 

• Colorless, yellow, yellow-green, brown, grey
• Chatoyant variety

Crystal System / Forms: 

Monoclinic System / Flattened, prismatic also massive compact.

Hardness: 

5.5

Specific Gravity: 

3.52 - 3.54

Cleavage / Fracture: 

Distinct 1 directional cleavage / Conchoidal to splintery fracture

Optic Character: 

Anisotropic, D.R., Biaxial positive

Lustre: 

Adamantine to Resinous

Refractive Index / Birefringence: 

1.900 - 2.034 / ± 0.134; Range: 1.880 - 2.193

Pleochroism: 

Strong: Pale yellow, brownish yellow and orangish brown / colorless, yellow and reddish yellow

Dispersion: 

0.051

Magnification: 

Crystals, fingerprints (spectral color in fingerprints due to dispersion), doubling

U.V. Fluorescence: 

Inert

Spectrum: 

Sometimes exhibits a 580nm - 595nm (didymium)

Cause of Color: 

• Yellowish green: Rare earth elements
• Intense green: Chromium

Specific Tests: 

Strong doubling and dispersion

Simulants (with separation tests): 

Natural Zircon (optic figure, dispersion, spectrum), Demantoid (optic character, inclusions), Synthetic Cubic Zirconia (optic character, lustre, S.G.), Synthetic Rutile (dispersion, S.G.), Peridot (R.I., dispersion, spectrum, inclusions), Chrysoberyl (R.I., spectrum, doubling, dispersion)

Geological Occurrence: 

Sphene occurs as an accessory mineral in igneous rocks and in metamorphic rocks such as schist and granite; often as fine crystals.

Sources: 

Sri Lanka, India (Tamil Nadu), Pakistan, Brazil, Madagascar, Mexico.

Cuts & Uses: 

Facetted cuts, cabochons, beads, etc.