Sphene (Titanite)

Titanite (also known as Sphene) is a beautiful gem with high dispersion, high refractive index (greater than Diamond), high birefringence and intense red, green and yellow colors. Unfortunately, it also has low hardness and is brittle so not recommenced for jewelry. Titanite is typically slightly to moderately included and clean gems are particularly rare and beautiful. Titanite may be mildly radioactive as defined in 49 CFR 173.403 (greater than 70 Bq/gram) due to the presence of the Rare Earth Elements (REE) Cerium (Ce), Lanthanum (La), Neodymium (Nd), Praeseodymium (Pr) and Samarium (Sm). Titanite may also be metamict. This means that the original crystal structure has been broken down and turned amorphous due to radiation damage. An intensly vivid green, chromium (Cr) rich variety of Titanite exists called Chromian Titanite. The main source of Chromian Titanite is the Saranovskii Mine, Saranovskaya Village, Gornozavodskii area, Permskaya Oblast’, Middle Urals Region, Russia.

Notable occurances of gemmy crystals of Titanite include Gilget and Badakhshan Provinces, Afghanistan; Pi~no Solo. From Campo do Boa, Capelinha, Minas Gerais, Brazil; Antsiranana and Tuléar Provinces, Madagascar; Skardu District, Baltistan, Northern Areas, Pakistan; and Subpolar Ural Mountains, Russia.

Chemical Formula: CaTiSiO5
  Calcium Titanium Silicate
Molecular Weight: 197.76 gm
Composition: Calcium 19.25 % Ca 26.94 % CaO
  La,Ce,Pr,Nd,Sm 3.64 % RE 4.25 % REE2O3
  Titanium 18.16 % Ti 30.29 % TiO2
  Aluminum 2.73 % Al 5.16 % Al2O3
  Iron 1.41 % Fe 2.02 % Fe2O3
  Silicon 14.20 % Si 30.38 % SiO2
  Oxygen 39.64 % O    
  Fluorine 0.96 % F 0.96 % F
   —  % F -0.40 % -O=F2
    100.00 %   99.60 % = TOTAL OXIDE


Crystallography: Monoclinic – Prismatic
Crystal Habit: Crystals wedge-shaped, flattened or prismatic by extension along [110], to 16 cm; compact, massive
Twinning: On [100], contact and penetration; less commonly lamellar on [221]


Cleavage: Distinct on [110], Imperfect on [100] and [112]; parting due to twinning on [221]
Fracture: Sub-Conchoidal
Tenacity: Brittle
Moh’s Hardness: 5.0 – 5.5
Density: 3.48 – 3.60 (g/cm3)
Luminescence: None
Radioactivity: Mild; GRapi = 3,805.77 (Gamma Ray American Petroleum Institute Units)
Other: May be metamict


Color: Colorless, Reddish Brown, Red, Yellow, Green, Gray, Black
Transparency: Transparent to Translucent, Opaque
Luster: Adamantine to Resinous
Refractive Index: 1.843 – 2.110  Biaxial ( + )
Birefringence: 0.100 – 0.160 (high)
Dispersion: Extreme; r > v
Pleochroism: Visible; distinct when deeply colored; X = nearly colorless; Y = yellow to green; Z = red to yellow-orange