A gemstone is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks and occasionally organic materials that are not minerals are also used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity and notoriety are other characteristics that lend value to gemstones.
Jewellery (UK) or jewelry (U.S.) consists of decorative items worn for personal adornment, such as brooches, rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the clothes. From a western perspective, the term is restricted to durable ornaments, excluding flowers for example. For many centuries metal such as gold often combined with gemstones, has been the normal material for jewellery, but other materials such as shells and other plant materials may be used.
Masonry is the building of structures from individual units, which are often laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, building stone such as marble, granite, and limestone, cast stone, concrete block, glass block, and adobe. Masonry is generally a highly durable form of construction. However, the materials used, the quality of the mortar and workmanship, and the pattern in which the units are assembled can substantially affect the durability of the overall masonry construction. A person who constructs masonry is called a mason or bricklayer. These are both classified as construction trades.
Opal is a hydrated amorphous form of silica (SiO2·nH2O); its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Due to its amorphous property, it is classified as a mineraloid, unlike crystalline forms of silica, which are considered minerals. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt.
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.
Tiles are usually thin, square or rectangular coverings manufactured from hard-wearing material such as ceramic, stone, metal, baked clay, or even glass. They are generally fixed in place in an array to cover roofs, floors, walls, edges, or other objects such as tabletops. Alternatively, tile can sometimes refer to similar units made from lightweight materials such as perlite, wood, and mineral wool, typically used for wall and ceiling applications. In another sense, a tile is a construction tile or similar object, such as rectangular counters used in playing games. The word is derived from the French word tuile, which is, in turn, from the Latin word tegula, meaning a roof tile composed of fired clay.
In gemology, chatoyancy, or chatoyance or cat's eye effect, is an optical reflectance effect seen in certain gemstones, woods, and carbon fibre. Coined from the French "œil de chat", meaning "cat's eye", chatoyancy arises either from the fibrous structure of a material, as in tiger's eye quartz, or from fibrous inclusions or cavities within the stone, as in cat's eye chrysoberyl.
Tumble finishing, also known as tumbling or rumbling, is a technique for smoothing and polishing a rough surface on relatively small parts. In the field of metalworking, a similar process called barreling, or barrel finishing, works upon the same principles.
Tracery is an architectural device by which windows are divided into sections of various proportions by stone bars or ribs of moulding. Most commonly, it refers to the stonework elements that support the glass in a window. The term probably derives from the tracing floors on which the complex patterns of windows were laid out in late Gothic architecture. Tracery can also be found on the interior of buildings and the exterior.
Moulding, also known as coving(United Kingdom, Australia), is a strip of material with various profiles used to cover transitions between surfaces or for decoration. It is traditionally made from solid milled wood or plaster, but may be of plastic or reformed wood. In classical architecture and sculpture, the moulding is often carved in marble or other stones.
Dzi bead is a type of stone bead of uncertain origin worn as part of a necklace and sometimes as a bracelet. In several Central Asian cultures, including that of Tibet, the bead is considered to provide positive spiritual benefit. These beads are generally prized as protective amulets and are sometimes ground into a powder to be used in traditional Tibetan medicine. Beads subject to this process have small "dig marks" where a portion of the bead has been scraped or ground away to be included in the medicine. Some dzi exhibit grinding and polishing of one or both ends, again the result of reduction for use in traditional Tibetan medicine or, in some cases, due to the bead's use as a burnishing tool in the application of gold leaf to thanka paintings or gilt bronze statuary.
Opalescence refers to the optical phenomena displayed by the mineraloid gemstone opal. However, there are three notable types of opal, each with different optical effects, so the intended meaning varies depending on context. The optical effects seen in various types of opal are a result of refraction or reflection (common) due to the layering, spacing, and size of the myriad microscopic silicon dioxide spheres and included water in its physical structure. When the size and spacing of the silica spheres are relatively small, refracted blue-green colors are prevalent; when relatively larger, refracted yellow-orange-red colors are seen; and when larger yet, reflection yields a milky-hazy sheen.
A bell jar is a glass jar, similar in shape to a bell, and can be manufactured from a variety of materials. Bell jars are often used in laboratories to form and contain a vacuum. It is a common science apparatus used in experiments. Bell jars have a limited ability to create strong vacuums; vacuum chambers are available when higher performance is needed. They have been used to demonstrate the effect of vacuum on sound propagation.
Go equipment refers to the board, stones, and bowls for the stones required to play the game of Go. The quality and materials used in making Go equipment varies considerably, and the cost varies accordingly from economical to extremely expensive.
Roughcast or pebbledash is a coarse plaster surface used on outside walls that consists of lime and sometimes cement mixed with sand, small gravel and often pebbles or shells. The materials are mixed into a slurry and are then thrown at the working surface with a trowel or scoop. The idea is to maintain an even spread, free from lumps, ridges or runs and without missing any background. Roughcasting incorporates the stones in the mix, whereas pebbledashing adds them on top.
A countertop, also counter top, counter, benchtop, worktop or kitchen bench, bunker is a raised, firm, flat, and horizontal surface. They are built for work in kitchens or other food preparation areas, bathrooms or lavatories, and workrooms in general. The surface is frequently installed upon and supported by cabinets, positioned at an ergonomic height for the user and the particular task for which it is designed. A countertop may be constructed of various materials with different attributes of functionality, durability and aesthetics, and may have built-in appliances, or accessory items relative to the intended application.
Pigmented structural glass, also known generically as structural glass and as vitreous marble, and marketed under the names Carrara glass, Sani Onyx, and Vitrolite, among others, is a high-strength, colored glass. Developed in the United States in 1900, it was widely used around the world in the first half of the 20th century in Art Deco and Streamline Moderne buildings. It also found use as a material for signs, tables, and areas requiring a hygienic surface. Over time, the trademarked name "vitrolite" became a generic term for the glass.
Ammolite is an opal-like organic gemstone found primarily along the eastern slopes of the Rocky Mountains of North America. It is made of the fossilized shells of ammonites, which in turn are composed primarily of aragonite, the same mineral contained in nacre, with a microstructure inherited from the shell. It is one of few biogenic gemstones; others include amber and pearl.1 In 1981, ammolite was given official gemstone status by the World Jewellery Confederation (CIBJO), the same year commercial mining of ammolite began. It was designated the official gemstone of the City of Lethbridge, Alberta in 2007.
Adularescence is an optical phenomenon that is produced in gemstones like moonstone. The optical effect is similar to labradorescence and aventurescence.
Slocum stone is an early opal simulant which was briefly popular prior to the introduction of synthetics and less expensive simulants. It was named after its inventor, John L. Slocum (1920–1998) of Rochester, Michigan.
