Sphene, also known as titanite is strongly pleochroic(yellow,green and brown) with a high double refraction and an adamanite lustre. The name “Sphene” comes from the Greek word, “sphen”, meaning “wedge”, which alludes to the formation of its crystals. Due to its strong dispersion, when brilliant-cut, Sphene can exhibit a fire similar to that of Diamond
Until recently, it was classed as a collectors’ stone.
COLOR, CLARITY & CUT
Sphene it is soft, at 5 to 5.5 on the Mohs scale, so consideration must be given to its mounting :rings would be vulnerable. It is sensitive to heat, which may change its colour, and to chemicals: ultra-sonic cleaning is best avoided .
Sphene can occur yellow, brown, green or reddish and various shades in between, such as cognac colour. Intense green Sphene is also known as “chrome Sphene”, due to the colour agent being chromium. “Chrome Sphene” and yellowish-green Sphene are the most desirable colours. Reddish Sphene gets its colour from manganese impurities and is sometimes referred to as “greenovit”
Sphene is rarely free from inclusions and eye clean stones are rare. Gemstones in sizes over 5 carats are also rare and are highly valued. Sphene has an adamantine lustre, which combined with its high dispersion, makes it an attractive gemstone.
Sphene is cut in a variety of faceted shapes that show off its high dispersion and adamantine lustre. Sphene can be seen in shapes such as octagons, trillions, squares, rounds and fancier shapes, such as ovals, pears and cushions. Translucent to opaque stones are often cut in cabochon . Sphene can present a challenge to lapidarists, due to its brittle tenacity and softness, but is worth the effort, since when faceted and polished it yields stunning results.
SPHENE GEMSTONE PROPERTIES:
|Chemical Formula:||CaTiSiO5 Calcium titanium silicate|
|Crystal Structure:||Monoclinic; platy|
|Colour:||Yellow, brown, green, reddish|
|Hardness:||5 to 5.5 on the Mohs scale|
|Refractive Index:||1.843 to 2.110|
|Density:||3.52 to 3.54|
|Transparency:||Transparent to opaque|
|Double Refraction or Birefringence:||0.100 to 0.192|
ORIGINS & IMITATION:
The Sphene Gem it is found in Burma, Brazil, Mexico, Austria, Sri Lanka, Canada and USA.
Sphene is known to occur with Scapolite, Apatite And Quartz. However, Sphene can be distinguished by its higher refractive index. Sphene also occurs with Zircon, which has a similar high refractive index. Sphene has a similar chemical structure to Tilasite, Malayaite And Fersmantite. Other gemstones that can be confused for Sphene are Chrysoberyl, Dravite, Golden Beryl, Scheelite, Topaz, Zircon and Idocrase.
NAME, FAME & LEGEND
Sphene has been known since 1787 and was named according to its titanium content in 1795 by Martin Klaproth. In 1801, it was given the name “Sphene” by French mineralogist, Rene Just Hauy. In 1982, the International Mineralogical Association Commission on New Minerals and Mineral Names (CNMMN) decided to use the name “titanite” rather than “Sphene”. However, both “Sphene” and “titanite” continue to be recognized in mineralogy circles, Sphene is the most frequently used gemology term. Sphene is said to be a calming and soothing stone that protects its wearer from negative energy. Additionally, Sphene is thought to aid clear thinking and creativity. Sphene in traditional Hindu is associated with the Ajna chakra; also known as the third eye, or brow chakra, which is related to the mind and previous lives. Physically, Sphene is thought to help alleviate muscle strain, fever and tissue inflammation.