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Jewelry Glossary -- In 1909, Julius Wodiska wrote a book entitled A Book of Precious Stones that included detailed information on various gems and minerals as well as an excellent study of Arts & Crafts jewelry.  It also provided a glossary of jewelry terms.


While it is somewhat dated (viz. the entry on x-rays), and uses British English spellings, it does contain useful information on jewelry nomenclature and use:




ACICULAR. Needle-like.

ADAMANTINE. Very hard--as hard as steel. From Adamas (Greek) ; Adamanta (Latin), the lustre of the diamond.

AGGREGATES. Clusters or groups.

ALLUVIAL. Washing away rocks, soil, or other mineral material from one place and depositing the debris in another.

AMORPHOUS. Without form, shapeless.

AMULET. From hamalet (Arabian), to carry. A charm, or talisman, worn on the person to ward off disease, accident, or other harm.

ARBORESCENT. Resembling a tree in appearance.

ASTERIATED. Radiated, with rays diverging from a centre, as in a star--as exhibited by an asteriated or star sapphire.

AVICULIDAE. Wing-shells, or Pearl Oysters.

AXIS. Axes or planes of crystals or other minerals--as demonstrated in crystallography.


BABY. Trough or cradle in which gravel was washed for diamonds by early South African diamond-seekers.

BAHIAS. Diamonds from the Bahia district, Brazil.

BASE. "Foundation price of a one-grain pearl from which to reckon prices of pearls of other weights. The price of pearls is quoted by the grain and reck­oned by the square; example: a two-grain pearl at three dollars base would be twice three dollars, or six dollars per grain 'flat'; and two grains at six dollars would be twelve dollars, the cost of the pearl." (From Precious Stones by W. R. Cattelle.)

BIREFRINGENCE. Double refraction of light of crystal minerals.

BIZEL. Portion of brilliant-cut diamond above the girdle.

BLEBBY. Blisters or bubbles in a crystal mineral

BLUE GROUND. Diamond-bearing clay of lower levels of South African diamond mines.

BLUE WHITE. Highest grade of South African diamonds.

BORT or BOART. Imperfectly crystallised form of dia­mond unfit for gems and used for pointing rock drills, for bearings of fine machinery and other tech­nical uses.

BOTRYOIDAL. A surface presenting a group of rounded projections.

BRECCIA. A not wholly formed rock of angular frag­ments naturally cemented by lime or some other ad­hesive mineral substance or "binder."

BRILLIANT. A style of diamond-cutting with fifty-six facets, exclusive of table and culet.

BRITTLE. A mineral, when it may be readily broken by a blow.

BRITTLE. A stone that breaks, or parts of it separate
into powder, when the attempt is made to cut it.

BROWNS. Eighth in list of principal trade terms in grad­ing diamonds.

BRUTING. Polishing diamonds by rubbing one against another.

BUBBLES. Small hollow specks in the body of a gem.

BUILT-UP RUBY. Reconstructed ruby.

BYON. Brownish-yellow clay in which occurs corundum-- rubies, sapphires, etc.

-- Ground adjacent to mother rock in which rubies have weathered out.

BYSSUS. Fibres, flaxy or silky in appearance, by which a mussel attaches its shell to wood or stone.

BY-WATERS. Yellow tinted diamonds.


CAPES. Diamonds with a yellowish tinge.

CAPILLARY. Hair-like.

CARAT. (Karat.) A unit of weight applied to precious stones varying in different trade centres. See table of weights of the carat in various localities in the Appendix.) The word carat is supposed to be de­rived from "Kuara," the bean-like fruit of an Af­rican tree reputed to have been used as a standard of

weight for precious stones. Karat is used to in­dicate degrees of quality in gold.

CARBON. A tetrad (having four sides), non-metallic min­eral element occurring in two crystalline forms, dia­mond and graphite, and one amorphous form, coal.

CARBON DIOXIDE. Carbonic acid gas; a colourless gas 1524 times as heavy as air and twenty-two times as heavy as hydrogen.

CARBON SPOTS. Opaque black spots in the body of a diamond.

CARBONADO. Brownish, black variety of diamond; large pebbles or masses of diamonds, nearly pure carbon. Carbonado was formerly chiefly found in great quantity--now decreasing--in Bahia diamond district, Brazil; used to point rock drills and, reduced to powder, for polishing diamonds.

CARBUNCLE. Garnet--sometimes, ruby, spinel, or other red gem--cut convex or en cabochon: there is no such specific mineral.

CAT'S-EYE. A term applied to gem minerals which, when cut convex (en cabochon), display a band of light, usually across inclusions of parallel fibres of as­bestos; name derived from resemblance to the eye of a cat.

CEYLON RUBY. A ruby having a pink tint.

CHALCEDONY PATCHES. Milk-like semi-transparent patches which sometimes occur as faults in rubies.

CHANGE OF COLOURS. Manifested in minerals like Labrado­rite, where the colours change as the stone is turned.

CHATOYANCY. Changeable or undulating lustre or colour, as displayed by a cat's-eye.

CHIPS. Cleavage of diamonds of smallest fractions of a carat in use.

CLATERSAL. Diamond splints, which are converted into diamond powder by crushing.

CLEAN. Free from interior flaws.

CLEAVAGE. Direction within a crystal along which there is minimum cohesion; diamond crystals which re­quire cleaving; pieces cleaved from the crystal.

CLEAVING. Splitting a crystal in a direction in which it may most easily be done--along the grain.

CLOSE GOODS. Pure stones, of desirable shapes; highest class of South African diamonds, as assorted at Kimberley.

CLOUDS. Muddy or cloudy patches of any colour in a stone which, when brought to the surface by cutting, are ineradicable. "Flat, subtransparent blotches along the grain of a stone."-- Cattelle.

COLOUR-PLAY. (Play of Colours.) Prismatic colours pro­duced by dispersion of light.

COLOUR RANGE. A statement of the various colours exhibited by different specimens of a mineral.

COMBUSTIBILITY. A quality possessed by the diamond only, among gems.

CONCENTRATES. Gem or mineral ore or ground reduced by mechanical or chemical processes to its minimum in bulk or weight.

CONCHOIDAL. Shell-like fracture of any mineral.

CONCRETIONS. Mechanical aggregation, or chemical union of particles of mineral forming balls or irregularly shaped nodules in strata of different material.

CONGLOMERATE. Pebbles or gravel bound together naturally by a silicious, alcareous, or argillaceous cement.

CORUNDUM. Crystallised alumina--rubies, sapphire, etc.

CRADLE. Trough in which, by a rocking motion, placer miners wash auriferous or gem gravels.

CRYSTALLOGRAPHY. The science which describes or delineates the form of crystals.

CRYSTALS. Trade term for fourth grade cut diamonds; colourless diamonds.

CULASSE. Portion of brilliant-cut diamond below the girdle.

CULET. (Or Collet). Bottom facet of brilliant parallel to the girdle.

CURATOR. One to whose official care is entrusted a de­partment--as of mineralogy--in a museum.


DIAMOND. The mineral gem alone composed of pure car­bon; crystallises in the isometric, or cubic, system; combustible, it can be totally consumed, disappearing in carbonic acid gas, when burned between the poles of a powerful electric battery.

DIAPHANEITY. The property of transmitting light.

DICHROISM. A property of all doubly refractive stones, of which the two images revealed by an instrument called dichroiscope appear in different colours.

DICHROSCOPE. An instrument designed to exhibit the two complementary colours of polarised light--the di­chroism of crystals.

DISPERSION. The power which decomposes a ray of com­mon white light in its passage through a transparent medium and splits it into the various colours of which it is composed.

DODECAHEDRON. A geometrical form in the isometric or cubic system applied to crystallography; a solid fig­ure of twelve equal sides, each a regular pentagon--of five equal sides and angles.

DOLOMITIC. Pertaining to dolomite, a brittle, translucent mineral of various colours and a vitreous lustre.


ERUPTIVE. Minerals of volcanic origin in geological formations.


FACET. One of the small planes which form the sides of a natural crystal, or of a cut diamond or other gem.

FALES. Stones of two, or more, differently tinted strata.

FALSE COLOUR. Effect of "False Stones."

FANCY. A term that has been applied to semi-precious stones prized for other qualities than intrinsic value.

FAULT. Anything within, or on the surface of, a pre­cious stone which detracts from its beauty or value; obvious examples are inclusions of foreign bodies and patches of a different colour or shade from the body of the gem.

FEATHERS. White subtransparent lines in the body of a stone.

FEMININE. Rubies of a pale tint.

FERROUS. Any mineral substance having a considerable portion of iron in its composition.

FIRE. Term applied to the lustre and brilliancy of gems, pre-eminently the diamond, and secondarily the opal.

FIRST BYE. (First By-water.) Diamond exhibiting a faint greenish tinge.

FIRST WATER. Diamonds so pure and colourless that they can scarcely be distinguished from water when im­mersed in it.

FISH-EYE. A diamond cut too thin to present the max­imum effect of brilliancy.

FIAT ENDS. Thin cleavages from the faces of a diamond crystal. 

FLATS. Thin, flat pieces of diamond crystal.

FLAW. A crack, defect, fault, fissure, or other structural imperfection in a gem.

FLUORESCENCE. The phenomenal quality exhibited by some gems of showing one colour in transmitted light and another in reflected light; fluorite, from which the word is derived, is a striking example.

FLUX. To melt, to fuse. As a noun, a fluid or substance which may be used to fuse some other material.
FRACTURE. Breaking a gem otherwise than the lines of cleavage.


GEM COLOUR. The most desirable colour for a stone.

GEMOLOGY. A word coined to supply a specific name for the science of gems.

GLASSIES. Octahedral diamond crystals (transparent).

GLASSY. Applied to diamonds which lack brilliancy.

GOLCONDA. Ancient and famous group of diamond mines on the Kistna River, India, where were found the Koh-i-noor and other world-famous diamonds.

GOLCONDAS. Diamonds from India.

GRAIN MARKS. Lines on the facet surfaces, the result of imperfect polishing.

GRAINERS. Diamonds which in weight will correspond to fourths of a carat; a diamond weighing one half a carat is a two-grainer; one weighing three quarters is a three-grainer; a diamond of one carat in weight is a four-grainer.

GRANITIC. Like, or of, granite.

GRANULAR. Composed of or resembling granules or grains.


HARLEQUIN. Most beautiful variety of opal.

HEMIHEDRAL. Having only half the planes or facets which a symmetric crystal of the type to which it belongs would possess; a crystal wanting some of its planes. (The hemihedral form in crystallography produces or aids the phenomena of pyroelectri­city.)

HEXAGONAL. Of the form of a hexagon; having six sides or angles.

HYDROSTATICS. Pertaining to the principles of the equilib­rium of fluids.


INCLUSIONS. Foreign substances within the body of a transparent mineral.

INDIAN-CUT. A style of diamond-cutting usually of In­dian or other Oriental origin in which the table is usually double the size of the culet; such stones are generally recut for European or American require­ments.

IRIDESCENCE. Descriptive of prismatic colours appearing within a crystal.

ISOMETRIC. The cubic system in crystallography.


JAGERS. Bluish-white diamonds of modern cut; originally diamonds from the Jagersfontein mine.

JIG. (Jigger; Pulsator.) A riddle or sieve shaken ver­tically in water to separate ore or gem gravel or ground into strata.


KNIFE-EDGE. The girdle of a brilliant cut to a sharp edge and polished.

KNOTS. Conditions found in diamonds as in wood, and troublesome to the lapidary.


LAPIDARY. One who cuts, polishes, or engraves precious stones.

LIGHT YELLOW. Seventh grade diamonds.

LUMPY. Stones cut thick.

LUSTRE. The optical character of a gem, dependent upon that portion of the light falling upon it which is reflected from the surface. Degrees of lustre: splen­dent, shining, glistening, glimmering. Kinds of lustre: metallic, vitreous or glassy, adamantine (the diamond's lustre), silky, satiny, pearly, nacreous, greasy, waxy, resinous.


MAACLES. Flat triangular diamond crystals or twin stones.

MACLED. Twinned crystals.

MASCULINE. A term applied to rubies of an intensely red hue.

MATRIX. The portion of rock in which a mineral is em­bedded. Gem minerals are sometimes cut together with a portion of the matrix and the matrix itself is sometimes cut and mounted like gems.

MELANGE. Diamonds of mixed sizes.

MELEE. Small diamonds.

METALLURGY. The art of separating metals from their ores or from impurities; smelting, reducing, refining, amalgamating, alloying, parting, brazing, plating, etc.

MINERALOGY. A science treating of those natural in­organic products of the earth which possess definite physical and chemical characters.

MONOCLINIC. Inclining in one direction.

MONOCLINIC SYSTEM. Having two of the axial intersec­tions rectangular and one oblique; having the lateral axes at right angles to one another, one of them be­ing oblique to the vertical axis and the other at right angles to it.

MOSSY. Term applied to emeralds clouded by fissures.

MUDDY. Imperfect crystallisation which obstructs the passage of light; exemplified by mud stirred in water.

MUFFLE. An oven-shaped vessel of baked fire-clay con­taining cupels or cups in which alloy is fused, or a furnace with a chamber surrounded by incandescent fuel.

MYTILIDAE. A family of conchiferous molluscs--pearl producing mussels.

MYTILIUS EDULIS. The true mussel.


NAATS. Thin flat crystals (diamond) used for "roses" and, by resplitting, for draw-plates.

NACREOUS. Lustre resembling mother-of-pearl, the lining of mollusc shells.

NIGHT EMERALD. Olivine, which loses its yellow tint by artificial light, showing only its green.

NOBLE. The highest type of a specified kind of gem, as "Noble Opal." A synonym of "Precious."

NODULES. A rounded irregular-shaped lump or mass, sometimes enclosing a foreign body in the centre.


OCCURRENCE. To be found existing.

OCTAHEDRON. Two four-sided pyramids united base to base.

OFF COLOUR. Having but a tint of desirable colour.

OLD MINE. Diamonds from the old Brazilian fields; old cut diamonds of good colour.

OPACITY. The quality or state of being impervious to light.

OPALESCENCE. A milky or pearly reflection from the in­terior of a stone.

OPALESCENT. Resembling or having the tints of opal; reflecting lustre from a single spot.

OPAQUE. When no light is transmitted.

OPTIC AXIS. The line in a double refracting crystal in the direction of which no double refraction occurs.

ORGANIC. Pertaining to the animal or vegetable kingdom.

ORIENTAL. A term much used in the gem trade to dis­tinguish stones of entirely differing chemical and crystallographic nature to which a common name is applied, as "Oriental topaz," bestowed on specimens of yellow corundum of gem quality.

ORIGINAL LOTS. Unbroken parcels of diamonds as graded and assorted at the mines.

ORTHORHOMBIC. (Trimetric.) Having three unequal axes intersecting at right angles.

OXIDE. The product of the combination of oxygen with a metal or metalloid.


PANNING. Primitive process of washing gravel by placer miners in search for gems.

PEARLY. Resembling the sheen of the pearl.

PERCUSSION. (Shaking Table.) A form of ore-separating apparatus consisting of a slightly sloping table on which stamped ore or metalliferous sand is placed to be sorted by gravity. A stream of water is directed over the ore, and the table is subjected to concusssion at intervals.

PHOSPHORESCENCE. The property possessed by substances of emitting light in certain conditions.

PIGEON BLOOD. A deep clear red; the gem colour of the most highly prized specimens of the ruby.

PLACER. A deposit of gem minerals found separately, sometimes as rolled pebbles, in alluvium or diluvium, or beds of streams.

PLAY OF COLOURS. (See colour-play.)

PLEOCHRISM. The term applied to minerals in which a different shade of colour is seen in more than two directions.

POLARISATION. In optics, a state into which the ethereal undulations which cause the sensation of light are brought under certain conditions.

POMEGRANATE. Translation of the Hindu name for spinel.

PRECIOUS. (See "Noble.")

PRIMARY SITUATION. A mineral found in the rock in which it was formed.

PRISM. ( Geometry.) A solid having similar and parallel bases, its sides forming similar parallel­ograms. (Optics.) Any transparent medium com­prised between plane faces, usually inclined to each other.

PROSPECTING. Searching for gem fields or mines.

PULSATOR. (See Jig; Jigger.)

PYROELECTRIC. (Thermo-electric.) Pertaining or relating to electric currents or effects produced by heat.


QUALITY. Native values of a gem irrespective of colour and cut.


RECONSTRUCTED. A term applied to an artificial gem composed of fused particles of a natural precious stone--"Reconstructed rubies" although not difficult to differentiate by tests, from the red corundum of gem quality from Nature's laboratory, attain some commercial success. Also called "Scientific Ruby."

REFLECTION. The act of reflecting or throwing back, as of rays of light.

REFRACTION. Bending back. In optics, the refraction of a ray of light into a number of other rays forming a hollow cone. Double Refraction: In crystals that are not homogeneous but have different properties of elasticity, etc., in different directions, if a ray of light enter the crystal in some particular directions it is not simply refracted but divided into two rays.

REJECTIONS. Diamonds not worthy of cutting.

RENIFORM. Kidney-shaped.

RESINOUS. The lustre of yellow resins; manifested in the common forms of garnets.

RHOMBS. Lozenge-shaped faces.

RIVERS. Diamonds found in the beds of rivers.

RONTGEN RAYS. (See X-rays.)

ROSETTE. (Rose-cut.) A form of cutting in which the stone's base is a single face; the general form is pyramidal and the several varieties each possess a different number of facets; a Double Rosette, also called "Pendeloque" is of the form of two rosettes joined at their bases.

ROUGH. Uncut crystals.

ROUND-STONES. Diamond crystals with arched facets.


SCHIST. A term used for rocks consisting of mineral ingredients arranged so as to impart a more or less laminar structure that may be broken into slabs or slaty fragments.

SECOND BYE. Fifth grade of rough diamonds.

SECOND CAPE. Third grade of South African rough dia­monds.

SEMITRANSPARENT. When objects are visible through a mineral, though the outlines are indistinct.

SHARPS. Thin, knife-edge pieces of diamond.

SLAMS. Dark, garnet-coloured rubies usually found in Siam.

SIGHT. Exhibition of rough diamonds by the London Syndicate to applicants for the privilege of inspecting and purchasing.

SILK. White, glistening streaks in the grain of rubies.

SILKY. A lustre suggesting silk, as exhibited by crocido­lite.

SILVER CAPES. Diamonds having a very slight tint of yellow.

SKIP. A bucket employed in narrow or inclined mine shafts, where the hoisting device must be confined between guides.

SMARAGDUS. Ancient name for emerald and other green stones.

SORTERS. The experts at the South African diamond mines who assort the rough diamonds.

SORTING TABLES. Tables on which rough diamonds are assorted.

SPECIFIC GRAVITY. The relative weight of bulk as com­pared with distilled water at 600 F.

SPECTRUM. The coloured image or images produced when the rays from any source of light are decomposed or dispersed by refraction through a prism.

SPLINTS. Thin, pointed pieces of diamonds.

SPREAD. Surface in proportion to the depth of a stone.

STAR STONES. Sapphires, and sometimes rubies, which by structure and cutting are seen to be asteriated, exhibiting a star of six rays of light.

STEP-CUT. (Trap-Cut.) A form of cutting employed for stones not deeply coloured when they are not cut as brilliants; a simple typical form is that of a stepped pyramid with the apex sliced off.

STREAK. Colour of the surface of a stone after being rubbed or scratched. "Streak-Powder" is the powder abraded from a stone.

STRIATED. Term applied to minerals which exhibit lines traversing the plane of a crystal; such lines bear a definite relation to certain forms of the mineral on which they occur.

SUBTRANSLUCENT. When the edges of a mineral only transmit light faintly.


TABLE-STONE. The typical form thus described is a style of diamond-cutting derived from an octahedron by cutting to opposite corners to an equal amount.

TAILINGS. The refuse part of washed gem ground, rock, or gravel which is thrown behind the tail of the washing apparatus and which is put through a second process to recover values possibly remain­ing.

TALCOSE. Partaking of the characters of talc.

TALLOW-TOPPED. A stone cut with a flattish convex sur­face.

TARIFF. Ten per cent. import duty imposed upon cut diamonds by the United States Government.

TETRAGONAL. Pertaining to a tetragon; having four an‑
gles or sides, as a square, quadrangle, or rhomb.

TETRAGONAL SYSTEM. A system of crystallisation in which the lateral axes are equal, being the diameters of a square, while the vertical is either longer or shorter than the lateral. Called also Dimetric, Mona­dimetric, or Pyramidal System.

TIFFANYITE. A hydrocarbon, causing phosphorescence and opalescence in some precious stones.

TOP CRYSTALS. Standard grade of diamonds.

TORN END. A three-cornered pyramid from the point of a wassie.

TRANSLUCENT. Minerals so nearly opaque that objects

are scarcely, if at all, visible through them.

TRANSPARENT. When the outlines of an object can be

seen through a gem distinctly.

TRICLINIC. The system in crystallography in which the three crystallographic axes are unequal, and inclined at angles which are not right angles, so that the forms are oblique in every direction, and have no plane of symmetry.

TWINNED. Two or more distinct crystals which have been formed in conjunction.


UNIAXIAL. Having one direction within the crystal, along which a ray of light can proceed without being bifurcated.

UNIO. The river mussel; the type-genus of Unionidae, with more than 400 species from all parts of the world.

URALIAN. Minerals from the Ural Mountains, Siberia.


VITREOUS. Glassy, as glassy lustre.


WASSIE. A large cleavage of a crystal split for cutting, as an octahedron divided into two pieces.

WAXY. A distinctive lustre, as of the turquoise.

WEATHERING. The disintegration and decay of minerals under the influence of the weather.

WELL. Name given to the dark centre of a diamond cut too thick.

WESSELTONS. Third grade cut diamonds.


X-RAYS. (Röntgen Rays.) A recently discovered form of radiant energy that is sent out when the cathode rays of a Crookes tube strike upon the opposite walls of the tube or upon any object in the tube; discovered in 1895 at Wiirzburg, Germany, by Professor W. C. Röntgen. By means of these rays it is possible to see and photograph bones, bullets, or other opaque objects through the fleshy parts of the body. The X-rays are of some value in testing mineral sub­stances represented as precious stones. Under X-rays the diamond is transparent; the glass, or "strass," used to manufacture imitation diamonds is always opaque under this exposure.


YELLOW GROUND. The upper diamond-bearing clay of South African mines.




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