Search results
Results from the WOW.Com Content Network
The mineral moissanite was discovered by Henri Moissan while examining rock samples from what is now called Meteor Crater located near Canyon Diablo, Arizona, in 1893. At first, he mistakenly identified the crystals as diamonds, but in 1904 he identified the crystals as silicon carbide.
As a gemstone used in jewelry, silicon carbide is called "synthetic moissanite" or just "moissanite" after the mineral name. Moissanite is similar to diamond in several important respects: it is transparent and hard (9–9.5 on the Mohs scale, compared to 10 for diamond), with a refractive index between 2.65 and 2.69 (compared to 2.42 for diamond).
Moissanite is superior to cubic zirconia in two ways: its hardness (8.5–9.25) and low SG (3.2). The former property results in facets that are sometimes as crisp as a diamond's, while the latter property makes simulated moissanite somewhat harder to spot when unset (although still disparate enough to detect).
This material is marketed as "mystic" by many dealers. Unlike diamond-like carbon and other hard synthetic ceramic coatings, the iridescent effect made with precious metal coatings is not durable, due to their extremely low hardness and poor abrasion wear properties, compared to the remarkably durable cubic zirconia substrate.
Metamorphic rocks are formed by subjecting any rock type—sedimentary rock, igneous rock or another older metamorphic rock—to different temperature and pressure conditions than those in which the original rock was formed. This process is called metamorphism, meaning to "change in form". The result is a profound change in physical properties ...
Peridot (/ ˈ p ɛ r ɪ ˌ d ɒ t,-ˌ d oʊ / PERR-ih-dot, -doh), sometimes called chrysolite, is a yellow-green transparent variety of olivine. Peridot is one of the few gemstones that occur in only one color. Peridot can be found in mafic and ultramafic rocks occurring in lava and peridotite xenoliths of the mantle.
Get the latest updates on the U.S. Elections. Stay informed with fast facts, candidate updates, and key takeaways on the issues, all in one place.
Gossan (eiserner hut or eisenhut) is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein. In the classic gossan or iron cap all that remains is iron oxides and quartz, often in the form of boxworks (which are quartz-lined cavities retaining the shape of the dissolved ore minerals).