EMAS (Au) gold A soft, heavy, yellow,

cubic mineral, the native metallic element Au. It is often naturally alloyed with silver or copper and occasionally with bismuth, mercury, or other metals, and is widely found in alluvial deposits (as nuggets and grains) or in veins associated with quartz and various sulfides. Gold is malleable and ductile, and is used chiefly for jewelry and as the international standard for world finance.

ANTIMON (Sb)

antimony (an'-ti-mo'-ny) A metallic white rhombohedral mineral, the native metallic element Sb. It is brittle and commonly occurs in silvery or tin-white granular, lamellar, or shapeless masses.

ARSEN (As)

arsenic (ar'-se-nic) A hexagonal mineral, the native metallic element As. It is brittle and commonly occurs in steel-gray and granular or kidney-shaped masses.

TEMBAGA (Cu)

copper (cop'-per) A reddish or salmon-pink cubic mineral, the native metallic element Cu. It is ductile and malleable, a good conductor of heat and electricity, usually dull and tarnished, and formerly an important ore. Copper is the only metal that occurs native abundantly in large masses; it frequently occurs in dendritic clusters or mossy aggregates, in sheets, or in plates filling narrow cracks or fissures. It has many uses, notably as an electric conductor and as the base metal in brass, bronze, and other alloys.

INTAN (C) diamond (di'-a-mond) (a) A cubic mineral,

representing a naturally occurring crystalline form of carbon dimorphous with graphite and being the hardest natural substance known (hardness of 10 on the Mohs scale). It often occurs in octahedrons with rounded edges or curved faces. Diamonds form under extreme temperatures and pressures and are found in ultrabasic breccias, pipes in igneous rocks, and alluvial deposits. Pure diamond is colorless or nearly so, color is imparted by impurities. When transparent and more or less free from flaws, it is the most cherished and among the most highly valued gemstones; its high refractive index and dispersive powers result in remarkable brilliance and play of prismatic color when faceted. Off-color or flawed diamonds are used for industrial purposes (such as in rock drills, abrasive powder, and cutting tools). (b) Artificially produced crystallized carbon similar to the native form. (c) A crystalline mineral that resembles diamond in brilliance, such as “Alençon diamond” (a smoky quartz sometimes valued as a jewel); esp. any of various kinds of rock crystal such as “Bristol diamond”, “Herkimer diamond”, “Lake George diamond”, and “Arkansas diamond”.

PERAK (Ag) silver (sil'-ver) A soft white

cubic mineral, the native metallic element Ag. It occurs in stringers and veins in volcanic and sedimentary rocks and in the upper parts of silver-sulfide lodes, and is often associated with small amounts of gold, mercury, copper, lead, tin, platinum, and other metals. Silver is ductile, malleable, and resistant to oxidation or corrosion, though it tarnishes brown; it has the highest thermal and electric conductivity of any substance. It is used for coinage, jewelry, and tableware, in photography, dentistry, and electroplating, and as a catalyst.

BELERANG (S)

sulfur (sul'-fur) (a) An orthorhombic mineral, the native nonmetallic element S. It occurs in yellow crystals at hot springs and fumaroles, and in masses or layers associated with limestone, gypsum, and anhydrite, esp. in salt-dome caprock and bedded deposits. Sulfur exists in several allotropic forms, including the ordinary yellow orthorhombic alpha form stable below 95.5ºC and the pale-yellow monoclinic crystalline beta form. Syn: brimstone. (b) A mining term used for iron sulfide (pyrite) occurring in coal seams and with zinc ores in Wisconsin and Missouri. Also spelled: sulphur.

GRAFIT (C) graphite (graph'-ite) A

hexagonal mineral, a naturally occurring crystalline form of carbon dimorphous with diamond. It is opaque, lustrous, greasy to the touch, and iron black to steel gray in color; it occurs as crystals or as flakes, scales, laminae, or grains in veins or bedded masses or as disseminations in metamorphic rocks. Graphite conducts electricity well, and is soft and unctuous, immune to most acids, and extremely refractory. It is used in “lead” pencils, paints, and crucibles, as a lubricant and an electrode, and as a moderator in nuclear reactors. Syn: plumbago; black lead.

BESI (Fe)

iron [mineral] A heavy, cubic, magnetic, malleable and ductile, and chemically active mineral, the native metallic element Fe. It has a silvery or silver-white color when pure, but readily oxidizes in moist air. Native iron occurs rarely in terrestrial rocks (such as disseminated grains in basalts), but is common in meteorites; it occurs combined in a wide range of ores and in most igneous rocks. Iron is the most widely used of the metals.

MERKURI (Hg)

mercury (mer'-cu-ry) A heavy, silver-white to tin-white hexagonal mineral, the native metallic element Hg. It is the only metal that is liquid at ordinary temperatures. Native mercury is found as minute fluid globules disseminated through cinnabar or deposited from the waters of certain hot springs, but it is unimportant as a source of the metal. It usually contains small amounts of silver. Mercury combines with most metals to form alloys or amalgams. Syn: quicksilver.