Amethyst is a violet variety of quartz. The name comes from the Koine Greek αμέθυστοςamethystos from α-a-, "not" and μεθύσκωmethysko / μεθώmetho, "intoxicate", a reference to the belief that the stone protected its owner from drunkenness. Ancient Greeks wore amethyst and carved drinking vessels from it in the belief that it would prevent intoxication.
Beryl ( BERR-əl) is a mineral composed of beryllium aluminium silicate with the chemical formula Be3Al2Si6O18. Well-known varieties of beryl include emerald and aquamarine. Naturally occurring hexagonal crystals of beryl can be up to several meters in size, but terminated crystals are relatively rare. Pure beryl is colorless, but it is frequently tinted by impurities; possible colors are green, blue, yellow, pink, and red (the rarest). It is an ore source of beryllium.
Emerald is a gemstone and a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium or sometimes vanadium. Beryl has a hardness of 7.5–8 on the Mohs scale. Most emeralds have many inclusions, so their toughness (resistance to breakage) is classified as generally poor. Emerald is a cyclosilicate.
A gemstone is a piece of mineral crystal which, when cut or polished, is used to make jewelry or other adornments. Certain rocks and occasionally organic materials that are not minerals may also be used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some softer minerals such as brazilianite may be used in jewelry because of their color or luster or other physical properties that have aesthetic value. However, generally speaking, soft minerals are not typically used as gemstones by virtue of their brittleness and lack of durability.
Spinel is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula MgAl
2O
4 in the cubic crystal system. Its name comes from the Latin word spinella, a diminutive form of spine, in reference to its pointed crystals.
Topaz is a silicate mineral made of aluminum and fluorine with the chemical formula Al2SiO4(F, OH)2. It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can make it pale blue or golden brown to yellow-orange. Topaz is often treated with heat or radiation to make it a deep blue, reddish-orange, pale green, pink, or purple.
Tourmaline is a crystalline silicate mineral group in which boron is compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. This gemstone comes in a wide variety of colors.
Ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum. Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapphires. Ruby is one of the traditional cardinal gems, alongside amethyst, sapphire, emerald, and diamond. The word ruby comes from ruber, Latin for red. The color of a ruby is due to the element chromium.
Zircon is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is ZrSiO4. An empirical formula showing some of the range of substitution in zircon is (Zr1–y, REEy)(SiO4)1–x(OH)4x–y. Zircon precipitates from silicate melts and has relatively high concentrations of high field strength incompatible elements. For example, hafnium is almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon is tetragonal crystal system. The natural color of zircon varies between colorless, yellow-golden, red, brown, blue, and green.
Lustre or luster is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the Latin lux, meaning "light", and generally implies radiance, gloss, or brilliance.
Pleochroism is an optical phenomenon in which a substance has different colors when observed at different angles, especially with polarized light.
Onyx is the parallel-banded variety of chalcedony, a silicate mineral. Agate and onyx are both varieties of layered chalcedony that differ only in the form of the bands. Onyx has parallel bands, while agate has curved bands. The colors of its bands range from black to almost every color. Specimens of onyx commonly contain bands of black or white or both. Onyx, as a descriptive term, has also been applied to parallel-banded varieties of alabaster, marble, calcite, obsidian, and opal, and misleadingly to materials with contorted banding, such as "cave onyx" and "Mexican onyx".
Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO3. In its pure form (rare), it is typically a rose-red colour, but it can also be shades of pink to pale brown. It streaks white, and its Mohs hardness varies between 3.5 and 4.5. Its specific gravity is between 3.45 and 3.6. The crystal system of rhodochrosite is trigonal, with a structure and cleavage in the carbonate rhombohedral system. The carbonate ions (CO2−
3) are arranged in a triangular planar configuration, and the manganese ions (Mn2+) are surrounded by six oxygen ions in an octahedral arrangement. The MnO6 octahedra and CO3 triangles are linked together to form a three-dimensional structure. Crystal twinning is often present. It can be confused with the manganese silicate rhodonite, but is distinctly softer. Rhodochrosite is formed by the oxidation of manganese ore, and is found in South Africa, China, and the Americas. It is one of the national symbols of Argentina and the state of Colorado.
In mineralogy, an inclusion is any material trapped inside a mineral during its formation. In gemology, it is an object enclosed within a gemstone or reaching its surface from the interior. According to James Hutton's law of inclusions, fragments included in a host rock are older than the host rock itself.
Amateur geology or rock collecting is the non-professional study and hobby of collecting rocks and minerals or fossil specimens from the natural environment. In Australia, New Zealand and Cornwall, the amateur geologists call this activity fossicking. The first amateur geologists were prospectors looking for valuable minerals and gemstones for commercial purposes. Eventually, however, more people have been drawn to amateur geology for recreational purposes, mainly for the beauty that rocks and minerals provide.
Elbaite, a sodium, lithium, aluminium boro-silicate, with the chemical composition Na(Li1.5Al1.5)Al6Si6O18(BO3)3(OH)4, is a mineral species belonging to the six-member ring cyclosilicate tourmaline group.
Goshenite is a colorless gem variety of beryl. It is called the mother of all gemstones because it can be transformed into other like emerald, morganite, or bixbite. Goshenite is also referred to as the purest form of beryl since there are generally no other elements present in the stone. The gem is used as imitation for diamond or emerald by adding colored foil on it.
Morganite is an orange or pink variety of beryl and is also a gemstone. Morganite is mined in Brazil, Afghanistan, Mozambique, Namibia, the United States, and Madagascar.
Red beryl, formerly known as bixbite and marketed as red emerald or scarlet emerald, is an extremely rare variety of beryl as well as one of the rarest minerals on Earth. The gem gets its red color from manganese ions embedded inside of beryllium aluminium cyclosilicate crystals. The color of red beryl is stable up to 1,000 °C (1,830 °F). Red beryl can come in various tints like strawberry, bright ruby, cherry, and orange.
Aquamarine is a pale-blue to light-green variety of the beryl family, with its name relating to water and sea. The color of aquamarine can be changed by heat, with a goal to enhance its physical appearance. It is the birth stone of March.
