Sphene

Sphene, the birthstone for July, boasts an extremely high refractive index and dispersion, and Gemtreejapan considers it a mineral that can be beautifully cut, a "specialty" of theirs.

Green sphene from Pakistan and chrome sphene from Russia, among others, are very beautiful and highly popular. Although sphene is found in several localities in Japan, it is generally considered a mineral specimen.

Sphene possesses a beauty that surpasses even that of diamonds, and due to its strong doubling effect, it gives the impression of even greater brilliance. However, its hardness is only half that of diamond, so while it makes eye-catching jewelry, care must be taken when handling it.

Name: Sphene / Titanite
Japanese Name: Titanite
Chemical Composition: CaTiSiO₅
Crystal System: Monoclinic
Specific Gravity: Approximately 3.52 – 3.54
Mohs Hardness: 5 – 5.5
Cleavage: Distinct
Luster: Adamantine to Vitreous
Transparency: Transparent to Translucent
Refractive Index: 1.88 – 2.05
Birefringence: 0.105 – 0.135
Color: Yellow, Green, Brown
Dispersion: 0.051