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Encyclopedia > Moissanite

Moissanite is a trade name given to silicon carbide (chemical formula SiC) for use in the gem business. As a gemstone, silicon carbide is similar to diamond in several important ways: it is transparent and extremely hard (9 1/4 on the Mohs scale, compared to 10 for diamond), with an index of refraction between 2.65 and 2.69 (compared to 2.42 for diamond). SiC has a hexagonal crystalline structure. Silicon carbide (SiC), also known as moissanite, is a ceramic compound of silicon and carbon. ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance dark gray, bluish tinge Atomic mass 28. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... A selection of gemstone pebbles made by tumbling rough rock with abrasive grit, in a rotating drum. ... A scattering of round-brilliant cut diamonds shows off the many reflecting facets. ... Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer. ... The refractive index of a material is the factor by which electromagnetic radiation is slowed down (relative to vacuum) when it travels inside the material. ... A regular hexagon A hexagon is a polygon with six edges and six vertices. ... Quartz crystal A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ...


Naturally occurring moissanite is extremely rare, as it is not formed naturally in any quantity within the Earth, and thus is found only in tiny quantities in certain types of meteorite and as microscopic traces in corundum deposits and kimberlite. Virtually all of the silicon carbide sold in the world, including moissanite gemstones, is synthetic. Natural moissanite was first found in 1905 as a small component of a meteorite in Arizona by Dr. Ferdinand Henri Moissan, after whom the material is named in the gem market. Synthetic silicon carbide has been known since 1892, when it was first produced by Edward Goodrich Acheson in his newly invented resistance furnace. Acheson named the material carborundum by analogy to corundum, another very hard substance (9 on the Mohs scale). Moissan's discovery of naturally occurring SiC was disputed at first due to the potential for contamination of his sample by silicon carbide saw blades that were already on the market at that time. Corundum is the crystalline form of aluminium oxide and one of the rock-forming minerals. ... Hewn kimberlite core sample from the James Bay Lowlands region of Northern Ontario, Canada. ... Generally, synthetic means pertaining to synthesis, i. ... 1905 (MCMV) was a common year starting on Sunday (see link for calendar). ... A meteorite is a small extraterrestrial body that impacts the Earths surface. ... Official language(s) English Capital Phoenix Largest city Phoenix Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 6th 295,254 km² 500 km 645 km 0. ... The French chemist Henri Moissan (1852--1907) won the 1906 Nobel Prize in Chemistry for his work in isolating fluorine from its compounds. ... Silicon carbide (SiC), also known as moissanite, is a ceramic compound of silicon and carbon. ... 1892 (MDCCCXCII) was a leap year starting on Friday (see link for calendar). ... Edward Goodrich Acheson (1856 - 1931) was a U.S. chemist. ... Silicon carbide (SiC) or moissanite is a ceramic compound of silicon and carbon. ... Corundum is the crystalline form of aluminium oxide and one of the rock-forming minerals. ...


In 1998 C3, Inc. (Charles and Colvard) [Nasdaq: CTHR], a subsidiary of Cree Research, Inc., introduced gem-quality synthetic silicon carbide onto the market under the name "moissanite," marketing it as a lower-cost alternative to diamond. For example, a 1 carat moissanite gem sells for about $600 (2005 USD), while a diamond of similar size and color typically runs for upwards of $4500. Synthetic moissonite is approximately as hard as diamond, with a slightly higher index of refraction and greater dispersion; these qualities make SiC a decent and durable diamond simulant. It is interesting to note that the higher dispersion and index of refraction means moissanite has more fire and brilliance than diamond. Silicon carbide (SiC), also known as moissanite, is a ceramic compound of silicon and carbon. ... This article addresses the many imitations of diamond. ...


While some properties of moissanite are closer to diamond than those of cubic zirconia, another synthetic diamond simulant, once its properties are known moissanite is perhaps even easier to identify. Jewellers were at first fooled by moissanite's thermal conductivity which approximates that of diamond, rendering older thermal testers useless; what worked with cubic zirconia did not work with moissanite. A round brilliant-cut cubic zirconia Cubic Zirconia (or CZ) is zirconium oxide (ZrO2), a mineral that is extremely rare in nature but is widely synthesized for use as a diamond simulant. ... In physics, thermal conductivity, λ or k, is the intensive property of a material which relates its ability to conduct heat. ...


Moissanite is harder than cubic zirconia (9 1/4 vs. 8 1/2), lighter (SG 3.33 vs. 5.6), and much more resistant to heat. This results in a stone of higher lustre, sharper facets and good resilience: loose moissanites may be placed directly into ring moulds, the stones remain undamaged from temperatures up to twice the 900°C melting point of 18k gold. General Name, Symbol, Number gold, Au, 79 Chemical series transition metals Group, Period, Block 11, 6, d Appearance metallic yellow Atomic mass 196. ...


See also

This article addresses the many imitations of diamond. ...

External links


  Results from FactBites:
 
Moissanite - Wikipedia, the free encyclopedia (489 words)
Naturally occurring moissanite is extremely rare, as it is not formed naturally in any quantity within the Earth, and thus is found only in tiny quantities in certain types of meteorite and as microscopic traces in corundum deposits and kimberlite.
Natural moissanite was first found in 1905 as a small component of a meteorite in Arizona by Dr. Ferdinand Henri Moissan, after whom the material is named in the gem market.
While some properties of moissanite are closer to diamond than those of cubic zirconia, another synthetic diamond simulant, once its properties are known moissanite is perhaps even easier to identify.
Moissanite (1707 words)
The present study of natural moissanite as well as that of synthetic α-SiC indicates that morphological criteria for the distinction between upper and lower forms are inadequate, and that etching is necessary for their reliable distinction.
The Bohemian moissanite is represented by a high-temperature α-SiC polymorph formed in the range from 1900 to 2000° C. This high temperature of formation and the presence of fragmental crystals indicate that the moissanite and associated volcanic breccia came from a great depth.
However, the moissanite in Bohemia is associated with distinctly hydrothermal minerals such as galena, pyrite and fluorite which normally form at shallower depths.
  More results at FactBites »

 
 

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