Berzelius as early as 1824, (Berzelius 1824). In 1891, Edward Goodrich Acheson produced viable minerals that could substitute for diamond as an abrasive and cutting material. This was possible, as moissanite is one of the hardest substances known, with a hardness just below that of diamond and comparable with those of cubic boron nitride and boron. Pure synthetic moissanite can also be made from thermal decomposition of the preceramic polymer poly(methylsilyne), requiring no binding matrix, e.g., cobalt metal powder. Single-crystalline silicon carbide, in certain forms, has been used for the fabrication of high-performance semiconductor devices. As natural sources of silicon carbide are rare, and only certain atomic arrangements are useful for gemological applications, North Carolina-based Cree Research, Inc., founded in 1987, developed a commercial process for producing large single crystals of silicon carbide. Cree is the world leader in the growth of single crystal silicon carbide, mostly for electronics use. In 1995 C3 Inc., a company helmed by Charles Eric Hunter, formed Charles & Colvard Ltd. (later changed to Charles & Colvard) to market gem quality moissanite. Charles & Colvard was the first company to produce and sell synthetic moissanite under U.S. patent US5723391 A, first filed by C3 Inc. in North Carolina. Applications Moissanite was introduced to the jewelry market as a diamond alternative in 1998 after Charles & Colvard (formerly known as C3 Inc.) received patents to create and market lab-grown silicon carbide gemstones, becoming the first firm to do so. By 2018 all patents on the original process world-wide had expired. Charles & Colvard currently makes and distributes moissanite jewelry and loose gems under the trademarks Forever One, Forever Brilliant, and Forever Classic. Other manufacturers market silicon carbide gemstones under trademarked names such as Amora. On the Mohs scale of mineral hardness (with diamond as the upper extreme, 10) moissanite is rated as 9.25. As a diamond alternative Moissanite has some optical properties exceeding those of diamond. It is marketed as a lower price alternative to diamond that does not involve the expensive mining practices used for the extraction of natural diamonds. As some of its properties are quite similar to diamond, moissanite may be used as counterfeit diamond. Testing equipment based on measuring thermal conductivity in particular may give results similar to diamond. In contrast to diamond, moissanite exhibits a thermochromism, such that heating it gradually will cause it to temporarily change color, starting at around