Mandarin garnet

From Wikipedia, the free encyclopedia

Mandarin garnet
Category	varietal species of spessartite
Chemical formula	Mn3Al2(SiO4)3
Identification
Color	orange-red
Crystal system	cubic [1]
Cleavage	none
Fracture	conchoidal [1]
Mohs Scale hardness	7 - 7.5 [1]
Luster	vitreous
Polish luster	vitreous to subadamantine [1]
Refractive index	1.78 - 1.81
Optical Properties	Single refractive, often anomalous double refractive [1]
Birefringence	none
Dispersion	.027 [1]
Pleochroism	none
Ultraviolet fluorescence	inert [1]
Specific gravity	4.15 (+.05, -.03)[1]

Mandarin garnets, also known as orange spessartite garnets, are naturally occurring stones found primarily in Africa that are known for their orange appearance. They are members of the spessartite family of garnets, and their chemical composition is that of silicate of magnesium and aluminium. It has a refractive index between 1.78-1.81, and a factor of 6.5-7.0 on Mohs hardness scale putting it with a given quartz crystal.

There is some debate as to what is a true mandarin and what is orange spessartite. The material that originates from Namibia is a pure glowing orange and is a highly desired stone. Those particular stones are found in Namibia only. However, there are other spessartites that are close in color and considered by many reputable retailers as well as some graduate gemologists to be as mandarin garnets .

If the stone is mainly orange, it's considered by definition to be a mandarin. However, the stones from Namibia are more saturated in color compared to those from places like Nigeria, Madagascar, etc. If a spessartite is more red than it is orange, then it's considered to be either an orange spessartite or red-orange spessartite.

Spessartite is considered a rare stone, but it is not widely known in many markets and is just becoming popular now. The mines are nearly stripped in most places. There are some mines in which there is believed to be deposits according to some of the major traders, but they say it is too dangerous to attempt to extract this mineral.

The most important deposits of this material are considered to be in Nigeria and Namibia. However, there are deposits in parts of South Africa, Madagascar, Sri Lanka, and a certain place in California. These things do variate in color though, and anything with brown overtones is considered to be less desirable.

Smaller stones can be found and of good quality. However, anything over 1 to 2 carats (200 to 400 mg) within what is deemed to be gem quality is considered to be rare. Anything over 5 carats (1 g) is considered even more rare, and the largest stones found in Africa have been in the 11 carat (2.2 g) range.

This material is distinctive in that is has a unique orange that is a lot more intense than that of an orange sapphire, but it's not as red as an almandine or Mozambique garnet. Material from Sri Lanka and California can be more of a yellow color than it is orange. Spessartite can range in color from yellow orange, or orange red.

[edit] References