The National Association of Goldsmith (N.A.G.) was established in 1894 to serve and support the Jewellery Industry of Great Britain and Ireland. The Association promotes high professional standards among its membership to inspire consumer confidence and t
Testing a gemstone on a refractometer prism, when the stone has a greater refractive index than the measuring prism of the device, or higher than the refractive index of immersion liquid used for optical contact, the scale of refractometer remains dark an
Synthetic alexandrite made in three methods in Russia, (a) growing synthetic stones of solution-growth process or flux process specially for alexandrite, (b) Growing stone of floating-zone process. (c) Melt-grown process or so-called pulling method.
OneMine collects the most relevant and reliable aggregation of technical papers associated with mining and minerals. Anyone can search OneMine, but only members of participating societies can view, download and print documents.
The placing of atoms or radicals in a crystal so that they point in a definite direction, or its crystallographic axes are in the conventional position.
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A light-colored, coarse-grained igneous rock from granite clan containing orthoclase, quartz, microline, mica, gemstones, and many ferromagnesian minerals resulting from slow solidification. Pegmatite is occurring place of many uncommon gem minerals such
Prized by collectors. Synthetic strontium titanate or fabulite found in a similar manner to perovskite. Natural counterpart of fabulite with the same composition is called tausonite.
The sum of homogeneous, physically distinct portion of matter in heterogeneous system, as the three phases; solid, liquid, or gas. Each phase may exist in different temperatures and pressures.
A special optical occurrence, or circumstance observed or are visible in certain gemstones such as chatoyancy, asterism, or play of color, adularescence, girasol, labradorescence, opalescence, schiller, etc.
Physical properties of gemstones are extremely important in understanding geological phenomena in synthesizing new materials, and identification of minerals. Physical properties and chemical composition of minerals change with temperature and pressure. P
Quantum of light or electromagnetic radiation, it can behave as a wave or as a particle. Traveling at the velocity of light. Photon have momentum but not mass or electrical charge. Also known as light quantum. Caused by excitation of atoms and molecules a
A variety of translucent, grayish-green to greenish yellow chatoyant quartz or chalcedony containing fine parallel fibers of asbestos or parallel channels, arranged through the stone at right angles to the eye and parallel to the base of the crystal, that
An unusual feature occur in Verneuil synthetic corundum by plunging of still heated stone into a much cooler liquid (thermal shock), which create fractures and it resemble closely to natural stone. By pursuing of this process developed honeycomb pattern d
An oily colorless, specific odor, insoluble, basic heterocyclic with the formula C9H7N. Composed synthetically by heating aniline, nitrobenzene, glycerol, and sulfuric acid. Used as food preservative and in the manufacture of dyes and antiseptics. R.I. -
The four quadrilateral facets of 8 main facets on the crown or on the pavilion of a brilliant-cut stone, which are also called bezel facets. The 4 on the crown touching the girdle with their apex and extending up to touch the table. There are four lozenge
The emission of particles or electromagnetic waves from a source such as nuclear radiation, X-rays, neutrons, gamma rays, electrons positive or negative, protons. Radiation has the effect of artificially altering color by artificially creating color cent
Radium treatment of minerals such as beryl to produce a bluish-white fluorescence only on the basal planes. Under SWUV and LWUV light beryl fluoresces bluish-white.