• Chemistry: SiC, Silicon Carbide
  • Class: Native Elements
  • Subclass: Non-metals
  • Group: Carbon
  • Uses: Only as mineral specimens, but artificial material has many uses especially as an abrasive, semi-conductor and as diamond simulants.
  • For Moissanite crystal mineral specimens see our For Sale or Sold lists
    For Moissanite Jewelry, see --> MOISSANITE JEWELRY

Moissanite is a mineral that was first discovered in fragments of the meteorite at Diablo Canyon or Meteor Crater in Arizona. It was named in honor of its discoverer, Nobel Prize winner Dr. Ferdinand Henri Moissan. Synthetic moissanite is also known as silicon carbide after its chemistry and by the trade name, carborundum. In the meteoritic material, moissanite is associated with tiny diamonds.  Moissanite is also the trade name being used for new synthetic SiC gemstones.

Moissanite grown in laboratories is now being cut as gemstones and they are used as diamond simulants. Moissanite brings to the jeweler's table a similar index of refraction and better than twice the fire of diamond, but is only slightly less expensive due to the difficulty in growing the crystals. Moissanite is causing quite a stir in the jewelry markets.

As a diamond simulant, artificial moissanite is very hard to differentiate from diamond and can fool many gemologists. It does have many similarities. It is very hard at 9.25 (diamond is 10) and it is highly refractive with an index of refraction of 2.6 - 2.7 (diamond's IR is slightly lower at 2.42). Most important, moissanite and diamond are thermally conductive unlike other diamond simulants and unfortunately it is this property that is primarily used as the test for the authenticity of real diamonds. Differences however are clear and other tests can be used to differentiate the two. First of all, moissanite is hexagonal, not isometric and therefore it is doubly refractive unlike diamond. A through-the-face examination of a moissanite gemstone should show double facet edges whereas a diamond's edges are single in appearance. Moissanite is also slightly less dense than diamond and is rarely perfectly clear of color, having pale shades of green. Natural flaws are absent in moissanite, replaced instead by tiny, unnatural, white, ribbon-like structures that are a result of the growing process. The synthetic SiC known as carborundum has seen many uses in high tech ceramics, electrical components, abrasives, ball bearings, semi-conductors, extremely hard saws and armor.

Natural moissanite is very rare and is limited to iron-nickel meteorites and a few other rare ultramafic igneous occurrences. Initially there were skeptics to the original meteorite findings and were attributed to the silicon carbide blades that may have been used to saw the type specimens. But this has been disputed because Dr Henri Moissan did not use silicon carbide blades to prepare the samples.

Moissanite can be a bi-product of the blast-furnace process used to make iron. In a blast furnace, the raw ingredients such as iron ore, carbon (usually in the form of coke, but other forms such as methane may be used), limestone and other chemicals and air (used to react with impurities) are continuously introduced. The reaction results in the production of pig iron which is removed as a liquid while the impurities form a slag which floats to the top and is removed. The sides of the huge furnace are relatively cool, while the interior is very hot, and this creates conditions for minerals to crystallize. Every few months, the furnace is emptied so that these minerals can be cleaned from the walls of the furnace. One such mineral is moissanite, which readily crystallizes from the silicon and carbon dissolved in the molten iron. The resulting moissanite crystals are nearly black and opaque due to their iron content, but they can be quite colorful and beautiful, although most are ground up and used as abrasives.

There are several phases of SiC. The original mineral discovered is officially known as moissanite-6H. The (6H) refers to the hexagonal symmetry of this phase of moissanite. There are two other phases recognized as minerals: moissanite-5H and the isometric phase beta-moissanite.

Moissanite is classified as an element despite the fact that in chemical reality it is a compound! The reason for this is that the elemental bonds that exist between carbon and silicon are very similar to the carbon-carbon bonds of other elemental minerals such as diamond. There also is just no other mineral class that moissanite could fit in better than the Native Elements Class! Moissanite in fact is sometimes placed into the Carbon Group which includes diamond and graphite. Additional justification lies in the structure of moissanite which is similar to the structure of diamond. Other chemically unusual Elements Class minerals that are found in meteorites include osbornite {TiN}, cohenite {Fe3C} and schreibersite {(Fe, Ni)3P}.


  • Color is green (although it may be nearly colorless to essentially black).
  • Luster is adamantine.
  • Transparency: Crystals are transparent to translucent.
  • Crystal System is hexagonal, trigonal and isometric.
  • Crystal Habits include tiny six-sided plates and grains in meteorites.
  • Hardness is 9.25
  • Specific Gravity is 3.1 - 3.2 (average)
  • Streak is white.
  • Other Characteristics: Index of refraction is 2.6 - 2.7, crystals are thermally conductive and highly double refractive.
  • Associated Minerals include iron meteorites and olivine.
  • Notable Occurrences include Diablo Canyon or Meteor Crater in Arizona and as a trace in several kimberlite deposits and placer deposits eroded from them.
  • Best Field Indicator is crystal habit, color, index of refraction, double refraction, density, thermal conductivity and especially hardness.
MOISSANITE specimens:
(hover for more info)
MOISSANITE specimen moi-1
$ 44.00
Dims:0.4x0.2x0.1" (1.0x0.5x0.3 cm)
Wt: 0.29ct
Unknown (laboratory created)
This specimen consists of a small hexagonal crystal of moissanite-the gem name for transparent silicon carbide. This specimen is deep green in color. This material is very hard-it will easily scratch glass. There is no damage to this specimen.
no photo
moi-1 ($ 44.00)
Unknown (laboratory created)
MOISSANITE specimen moi-2
$ 39.00
Dims:0.3x0.2x0.1" (0.8x0.5x0.3 cm)
Wt: 0.26ct
Unknown (laboratory created)
This specimen consists of several small intergrown crystals of moissanite-the gem name for silicon carbide. The color of this piece varies from a medium to a dark gree. It is undamaged.
no photo
moi-2 ($ 39.00)
Unknown (laboratory created)
MOISSANITE specimen moi-3
$ 80.00
Dims:0.6x0.3x0.1" (1.5x0.8x0.3 cm)
Wt: 0.53ct
Unknown (laboratory created)
This is a hexagonal shaped crystal of moissanite-the gem name for silicon carbide. The color of this specimen ranges from a medium to a dark green. There is no damage to this piece.
no photo
moi-3 ($ 80.00)
Unknown (laboratory created)
MOISSANITE specimen moi-4
$ 60.00
Dims:0.3x0.3x0.1" (0.8x0.8x0.3 cm)
Wt: 0.40ct
Unknown (laboratory created)
This is a partial crystal of moissanite-the gem name for silicon carbide. The crystal shows some hexagonal faces. The color ranges from a light green to dark green. One side of this specimen shows some damage where another crystal was removed.
no photo
moi-4 ($ 60.00)
Unknown (laboratory created)
MOISSANITE specimen moi-5
$ 59.00
Dims:0.5x0.3x0.1" (1.3x0.8x0.3 cm)
Wt: 0.39ct
Unknown (laboratory created)
This specimen consists of a hexagonal crystal of moissanite-the gem name for silicon carbide. this piece is a very attractive light green in color. One side of this specimen is damaged where it was broken away from the host material.
no photo
moi-5 ($ 59.00)
Unknown (laboratory created)
MOISSANITE specimen moi-6
$ 35.00
Dims: 5.21x3.43x1.73" (13.24x8.72x4.40cm)
Wt: 13.0oz (368g)
This moissanite specimen is a typical cluster of silicon carbide crystals that precipitated on the walls of a blast furnace during the manufacture of steel. As such, it has a black color (due to a high level of iron impurities) and the crystals are opaque. They do have an excellent vitreous luster, and a colorful irridescent tarnish. The larger crystals are well formed thin hexagonal blades, while about half of the surface is covered by smaller distorted crystals that are often curved.
no photo
moi-6 ($ 35.00)
MOISSANITE specimen moi-7
$ 30.00
Dims: 6.73x3.58x2.31" (17.09x9.11x5.87cm)
Wt: 30.37oz (861g)
This is a large colorful moissanite specimen, crystallized on the wall of a blast furnace during the production of steel. Moissanite (silicon carbide), is exceedingly hard (only diamond beats it), but the specimen is still rather brittle. Instead of being transparent, it is colored black due to the heavy concentration of iron impurities. The surface of the moissanite displays bright irridescent hues of blues, purples, and golds. The crystals are all flat with prismatic shapes, and while I do not see any hexagonal crystals, the angles indicate hexagonal form. Many of the crystals have interesting growth patterns on their surfaces. Many small pieces will fall off duing handling (and shipping, for that matter), but this will not detract from the specimen's appeal.
no photo
moi-7 ($ 30.00)
MOISSANITE specimen moi-8
$ 45.00
Dims: 4.78x3.95x2.67" (12.13x10.02x6.77cm)
Wt: 15.70oz (445g)
I like this moissanite specimen. It stands on its own quite nicely, has a cavity (and two exposed areas that were cavities until the adjacent mineral was removed), and the cavity is nearly round, and my first thought was that it was a drill hole, but then I noticed the excellent crystals growing into the cavity. These areas expose nearly perfect silicon carbide crystals that are larger than on the rest of the specimen, although in general the tiny crystals on the base yield to larger and larger ones towards the top. The colors are excellent here, too, with the violet, purple, and blue hues at the base yielding to greens, blues, and even nearly yellow irridescent hues near the top.
no photo
moi-8 ($ 45.00)
MOISSANITE specimen moi-9
$ 35.00
Dims: 5.68x3.13x2.52" (14.44x7.95x6.40cm)
Wt: 18.31oz (519g)
This moissanite specimen has especially brilliant irridescent colors in shades of blue, purple, green, and gold. It has an interesting shape at the top where the colors are most intense. Of course, like all such specimens, this one was formed in a blast furnace as an unintended by-product of the steel making process.
no photo
moi-9 ($ 35.00)
MOISSANITE specimen moi-10
$ 25.00
Dims: 5.16x1.67x1.35in (13.12x4.24x3.44cm)
Wt: 4.20oz (119g)
This colorful moissanite specimen can almost be described as a frozen rainbow - it displays a nearly continuous change of irridescent colors from gold through purple and blue to green.
no photo
moi-10 ($ 25.00)
MOISSANITE specimen moi-12
$ 30.00
dims mm=123.16x75.19x69.14
wt g=439
The base of this chunk of moissanite (silicon carbide) is gray with bits of other materials from the blast furnace still attached. The sides are irridescent in shades of blue and green, while the top adds hues of purple. Some of the largest crystals (all are small) display irridescent hues from the entire rainbow.
no photo
moi-12 ($ 30.00)


Copyright ©1995-2023 by Amethyst Galleries, Inc.