Marble is a metamorphic rock formed under the influence of heat and pressure and consists of a mass of interlocking calcite or dolomite crystals. Pure marble is white, and some other marbles take their common names from their color or mineral impurities. Marble is often used for fine building material or sculpture, thanks to its beautiful appearance.
Marcasite is a polymorph of pyrite. It has the same chemistry, but a different crystal structure. In the jewelry trade, the names pyrite and marcasite are often used interchangeably. Marcasite is often cut and polished in a cone or pyramid shape and pave set between sterling silver beads to enhance their brilliance.
Maw-sit-sit is a rock composed primarily of kosmochlor with varying combinations and amounts of other minerals. Due to its close resemblance to jade, it was believed to be a variety of jade up until the 1960s. This gem is opaque saturated green with dark green to black veining or mottling.
Melo Melo Pearl
The Melo Melo pearl comes from the Melo Melo sea snail, a group of sea snails with scroll-like volute shells found in the South China Sea. The melo pearl is a non-nacreous pearl with colors ranging from light tan to brown, but orange is the most sought-after color. Melo Melo pearls are extremely rare, as no harvesting techniques exist.
Mesolite is a zeolite mineral that occurs in delicate, needle-like crystal structures that radiate from its base. Prized by collectors for its striking crystal formation, mesolite is typically white or colorless, but occasionally light yellow in color. Large specimens are very rare, and faceted gems are almost non-existent.
A meteorite is a solid piece of debris that originated in outer space, entered Earth's atmosphere, and survived impact with the surface. These fragments are usually from comets or asteroids, or debris from the Moon or Mars. There are several known meteorite impact sites, including Campo Del Cielo, Argentina, the Sikhote Alin Mountains in Primorye, Russia, and the Sahara Desert region of Morocco. Meteorites are separated into three types based on their metal content: iron, stony-iron and stony.
Mimetite is a lead-arsenate mineral belonging to the apatite group. It forms a series with vanadinite and pyromorphite. For this reason, the mineral is named for the Greek word for imitator due to its resemblance to pyromorphite.
Synthetic moissanite is an incredibly durable gem. In fact, the ceramic version of synthetic moissanite, called synthetic silicon carbide, is so hard and tough that it is used for body armor and mirrors in orbiting space telescopes! Fortunately, it also makes a gorgeous gem. Synthetic moissanite has a higher dispersion value (fire) than diamond, making it an impressive jewel. Each lab created gem is faceted by a skilled cutter to maximize its brilliance and enhance its exceptional fire. Second in hardness only to diamond, it is extremely resistant to scratching, abrasion, breaking and chipping.
Moldavite is a silica rich tektite found near the Moldau River in Czechia. Moldavite is a natural glass formed as a result of a meteorite impact with the earth. It was first discovered in the late 1700’s in what was then known as western Moravia. The colors of moldavite range from yellowish green to green and brownish green.
Montebrasite is a light green to yellow or colorless gemstone that belongs to the amblygonite group. Similar to amblygonite in chemical composition, it has less fluorine content and twinned crystals are common. Montebrasite was named for its discovery in Montebras, France.
Mookaite comes in the warm earthy colors of reds, yellows, and browns. It is a silica-rich porcelanite (a natural ceramic) created by the weathering of a special rock deposit in Western Australia. It owes its bold colors and texture to its variable composition. In 2011 pink mookaite was discovered at the Binthalya prospect.
Moonstone is a variety of feldspar that displays an amazing optical phenomenon called adularescence. Internally repeating feldspar layers scatter the light that enters the stone, creating a mystical glow reminiscent of moonbeams. This glow comes to life, rolling across the gem’s surface, when it is moved. Adularescent labradorite with a multi-colored glow is sometimes called Rainbow Moonstone.
Morganite is the pretty, peachy-pink variety of beryl, cousin to more familiar beryl varieties, emerald and aquamarine. Morganite's beautiful, feminine colors are a result of the presence of manganese and iron. After its 1910 discovery in Madagascar, the famous gemologist George F. Kunz proposed to name the gem in honor of financier and gem enthusiast J. P. Morgan. Morganite has many redeeming qualities, including good Mohs hardness, luster, and clarity. The two major sources are Brazil and Madagascar. Stones also come from Afghanistan, China, Mozambique, Namibia, Pakistan, Russia, and the United States. Quality morganite stones in large sizes remain relatively rare.
Mother-of-pearl is the nacreous iridescent inside layer of certain mollusks. This beautiful substance is often used for jewelry, carving and ornamentation. As mother-of-pearl producing mollusks cannot regulate their body temperature, they are susceptible to changes in external conditions. Mother-of-pearl can naturally appear in a wide variety of colors, however, it is frequently dyed to a multitude of attractive shades.
The Italian glass industry dates to the 8th century. In 1291, Venetian glassmakers were ordered to move to the island of Murano to prevent fire from destroying the wooden buildings of Venice. Glass artisans handed down their knowledge and skills through the generations. The Murano artists are forever innovating, and they are known for their use of color and intricate glass decorations.
Muscovite specimens are prized by collectors. Muscovite Mica is commonly used as a component in cosmetics, like eyeshadow, to produce shimmer.
The chemical vapor deposition (CVD) process deposits a thin film onto part of the surface of a colorless quartz gemstone, creating an eye-catching rainbow effect as light passes through the gem, which results in an unbelievable array of colors.
With its dazzling kaleidoscope of colors, Mystic Topaz® first appeared in September 1998 at the Hong Kong Jewelry Fair, but it took a few years for designers and high-end jewelry manufacturers to realize its unquestionable charm. Mystic Topaz® begins with a natural topaz gemstone that was created millions of years ago, that is then made even more beautiful and desirable with the assistance of modern technology. The chemical vapor deposition (CVD) process deposits a thin film onto part of the surface of a white topaz gem, creating an eye-catching rainbow effect as light passes through the gem, which results in an unbelievable array of colors.
Nanocrystal is glass-ceramic material developed in the 1970’s. Nanocrystal can simulate most gem materials and comes in a variety of colors and transparencies.
Natrolite is a zeolite mineral named for the Greek word natron, meaning "soda," due to the presence of sodium in the stone. Its range of colors include yellow, gray, and brown, to colorless. Occasionally, it is found in pale yellow to red hues. Crystals often grow in long, needle-like formations, and are especially prized by specimen collectors.