What is the chemical composition for titanite?
What is the chemical composition for titanite?
Titanite, or sphene (from the Greek sphenos (σφηνώ), meaning wedge), is a calcium titanium nesosilicate mineral, CaTiSiO5. Trace impurities of iron and aluminium are typically present. Also commonly present are rare earth metals including cerium and yttrium; calcium may be partly replaced by thorium.
What mineral group is titanite in?
titanium
Sphene or titanite belongs to the titanite mineral group as the titanium-rich (Ti) member. It’s the only member of this group commonly used as a gemstone. While mineralogists officially use the term titanite to refer to this stone, many gemologists use the term sphene.
What is a sphene stone?
Sphene is a very rare brilliant yellowish-green, green, orange or brown gemstone with a high luster, also known as “titanite” due to its titanium content. The name “sphene” comes from the Greek word, “sphen”, meaning “wedge”, which alludes to the formation of its crystals.
Why is sphene called titanite?
Titanite is named for its titanium content. Its alternate name Sphene is named from the Greek term “sphenos”, which means wedge, in allusion to the typical wedge-shaped crystals exhibited by this mineral. For additional information, see the gemstone section on Sphene.
Where is Sphene found?
The primary sources of sphene are Canada, Madagascar and Mexico, IGS says. Baja California, Mexico produces yellow-brown, brown, green and dark green (chrome) crystals up to 4 inches long, making it one of the world’s main sphene deposits.
How is titanite made?
Titanite is a rare mineral. It occurs as an accessory mineral in a few igneous rocks that include granite, granodiorite, diorite, syenite, and nepheline syenite. It is sometimes present in marble or calcium-rich gneiss and schist. The best crystals are usually found in marble.
What color is Sphene gemstone?
yellowish green
Sphene is the gemstone variety of the mineral titanite (named for its high titanium content). It falls around the middle of the Mohs hardness scale, at around 5 to 5.5. It ranges in color from a yellowish green to orange-brown.
What color sphene is most valuable?
IGS also notes that “chrome sphene”—dark green in color—is the most valuable type as its hue mimics a good emerald.
Is sphene safe to wear?
Unfortunately sphene is not as suitable for jewelry as some other gemstones, but it can certainly be worn in a necklace, pendant or a pair of earrings if you take good care of it.
How do you identify sillimanite?
Sillimanite is a metamorphic mineral found in high grade aluminous schists and gneisses. It is a polymorph of andalusite and kyanite, all having formula Al2SiO5. Keys to identification are high relief, needle-like, fibrous or bladed habit, characteristic square cross sections with one diagonal cleavage.
What is the meaning of sphene?
Definition of sphene : a mineral that is a silicate of calcium and titanium and often contains other elements.
What are zircons made of?
zirconium silicate mineral
Zircon is a zirconium silicate mineral with a chemical composition of ZrSiO4. It is common throughout the world as a minor constituent of igneous, metamorphic, and sedimentary rocks. Zircon is a popular gemstone that has been used for nearly 2000 years. Today it serves as a modern birthstone for the month of December.
Are there minerals for sale on Mindat.org?
Mindat.org does not offer minerals for sale. Mindat.org is affiliated with the Friends of Mineralogy. Their mission is to promote, support, protect and expand the collection of mineral specimens and to further the recognition of the scientific, economic and aesthetic value of minerals and collecting mineral specimens.
When did titanite start to be called sphene?
Titanite is frequently called by the name Sphene, which was the more popular term for this mineral prior to 1982. In 1982, the IMA adopted the official name as Titanite and discredited Sphene. The name Sphene is still frequently used, especially in Europe.
Where are green titanite crystals found in Africa?
In Africa, lustrous brown and green Titanite crystals are found in Imilchil, Morocco; and olive-green, transparent, flattened twins come from Ankarafa, Antsiranana Province, Madagascar. Brazil has produced exceptionally large, gemmy, olive-green green crystals that are often twinned at Capelinha, Minas Gerais.
