THE MINERAL SPHENE

Chemistry: CaTiSiO5, Calcium Titanium Silicate
Class: Silicates
Subclass: Nesosilicates
Uses: Mineral specimens, source of TiO2 (a pigment) and as a gemstone.
Specimens

Sphene is named from the greek word for wedge, because of its typical wedge shaped crystal habit. It is also alternatively called titanite for its titanium content. Spene can be cut as gems although it is considered a rarity on the gem market. It brings to the table a fire greater than diamond and unique color shades. However its softness limits its desirability as a gemstone. Twinning is common in sphene and forms a classic twin shape that is found mostly in Pakistan. The twin is shaped like a deflated, caved-in football, only with flatter surfaces. Spene can form nice crystals and can make a lovely addition to the collection of a collector who appreciates different crystal forms.

PHYSICAL CHARACTERISTICS:

Color is green, yellow, white, brown or black.
Luster is adamantine.
Transparency: Crystals are transparent to translucent.
Crystal System: Monoclinic; 2/m
Crystal Habits include elongated wedges that form tabular or platy crystals. Some crystals are not so elongated and can have a trigonal appearance similar to a flattened rhombohedron. Twinning is common and produces a twin that is shaped like a deflatted, caved-in football, only with flatter surfaces.
Cleavage is indistinct in two directions
Fracture is conchoidal
Hardness is 5 - 5.5
Specific Gravity is 3.3 - 3.6
Streak is white.
Associated Minerals are chlorite, anatase, calcite, quartz, zircon and feldspars.
Other Characteristics: Pleochroic if strongly colored.
Notable Occurances include Gilget, Pakistan; Mt Vesuvius, Italy; Kola Penn., Russia; Ontario, Canada and New York and California, USA.
Best Field Indicators are crystal habit, luster, hardness, twinning if present and color.