Glossary Archive

B

Bezel setting: A bezel setting is a thin rim of metal that wraps all or part of the way around the edge of a gemstone to hold it firmly in place.
Brilliance: Brilliance is the white light that a cut gemstone sends back to your eye when you look at it from the top, which makes it look bright and full of life. used in 11 places

C

CAD: CAD (computer-aided design) is computer software used to build a detailed 3D model of a piece of jewellery, so it can be seen and changed before it is made.
Carat: A carat is the unit used to weigh gemstones, so it tells you how heavy a stone is, not how big it is. used in 32 places
Clarity: Clarity describes how free a diamond is from tiny marks inside it, called inclusions, and marks on its surface, called blemishes, as seen under 10× magnification.
Claw setting: A claw setting holds a gemstone in a ring with small metal tips, called claws or prongs, that rise from the ring and bend over the edge of the stone.
Colour grade: A colour grade is a letter from D to Z that tells you how colourless a white diamond is, with D meaning no colour at all and Z meaning a clear light yellow or brown tint.
Crown: The crown is the top part of a cut diamond or other faceted gemstone, from its widest edge (the girdle) up to the flat top facet (the table).
Culet: The culet is the tiny point or small flat facet at the very bottom of a diamond, where the lower facets meet. used in 2 places
Cut grade: A cut grade is a rating of how well a diamond has been cut, judging how its angles, proportions and finish send light back to your eye so it looks bright and lively.
CVD (chemical vapour deposition): CVD (chemical vapour deposition) is a way of making laboratory-grown diamonds by breaking down a carbon-rich gas so that carbon builds up on a small diamond seed, layer by layer.

D

Dispersion (fire): Dispersion is the way a gem splits white light into rainbow colours, and fire is the name for the coloured flashes you see when the stone or the light moves. used in 10 places

F

Fancy colour diamond: A fancy colour diamond is a diamond whose colour, such as yellow, pink, blue or green, goes beyond the normal range used to grade ordinary diamonds.
Fire: Fire is the flashes of rainbow colour you see in a diamond as it moves, caused when the stone splits white light into its separate colours.
Fluorescence: Fluorescence is a glow that some diamonds and gemstones give off while ultraviolet (UV) light, such as the UV in daylight, shines on them. In diamonds, the glow is usually blue. used in 6 places
Fracture filling: Fracture filling is a treatment that fills cracks reaching a gemstone's surface with glass, resin, wax or oil, so the cracks are harder to see. used in 10 places

G

Girdle: The girdle is the thin outer edge around the widest part of a diamond, where the top half meets the bottom half, and it is the edge the setting holds. used in 22 places
Grading report: A grading report is a document from a gem laboratory that describes a diamond's qualities, such as its weight, colour and clarity, but does not say what it is worth.

H

Hallmark: A hallmark is a set of tiny marks stamped on gold, silver, platinum or palladium by an assay office, an independent metal-testing office, to show the metal and its purity. used in 2 places
Halo setting: A halo setting is a ring design where a circle of small stones surrounds the main stone, adding sparkle and often making the main stone look bigger.
Hidden halo: A hidden halo is a row of tiny stones set just below a ring's main stone, so you can't see them from above, but they sparkle when you look from the side.
HPHT: HPHT stands for high pressure, high temperature: a way of using intense heat and pressure to grow a diamond in a lab, or to change the colour of a diamond that already exists.

I

Inclusion: An inclusion is a feature inside a gemstone, such as a tiny crystal, bubble or crack, and it can be found in both natural and laboratory-grown stones. used in 24 places

K

Karat: Karat is a measure of how pure gold is: it tells you how much of a piece of metal is gold and how much is other metals mixed in.

L

Lattice diffusion: Lattice diffusion is a gem treatment that uses heat and added chemicals to push a colouring element into a stone, changing its colour, sometimes only near the surface. used in 5 places

M

Mohs scale: The Mohs scale ranks gems and minerals from 1 to 10 by how well they resist scratching, from soft talc at 1 to diamond, the hardest, at 10. used in 12 places

P

Pavé setting: A pavé setting covers a ring's metal with many tiny stones set close together, each held by small beads of metal, so the surface looks paved with sparkle.
Pavilion: The pavilion is the lower, pointed part of a diamond, below its widest edge. Its angled facets reflect light back up, so it shapes how bright the stone looks. used in 10 places
Platinum: Platinum is a heavy, naturally white precious metal that is used to make rings and other jewellery.
Pleochroism: Pleochroism is when a gemstone shows different colours as you turn it, because its crystal absorbs light differently in different directions. used in 5 places

R

Refractive index: Refractive index is a number that tells you how much a material slows down and bends light as the light passes into it, such as from air into a gemstone.
Rhodium plating: Rhodium plating is a very thin coating of rhodium, a shiny, silvery-white metal, added to jewellery such as white gold to make it look brighter and whiter.
Rose gold: Rose gold is gold mixed with copper, and sometimes a little silver, which gives the metal a soft pink colour instead of the yellow of pure gold.

S

Scintillation: Scintillation is the sparkle you see when a diamond, you or the light moves: quick flashes of light, plus the shifting pattern of bright and dark areas across the stone.
Shank: The shank is the band of a ring: the round strip of metal that goes around your finger and holds up the part with the stone.
Solitaire setting: A solitaire setting is a ring design with one single centre stone and little or no extra decoration, so all the attention goes to that one stone.

T

Table: The table is the flat facet on the very top of a cut gemstone, usually the largest one, that you look through when the stone faces up. used in 10 places
Three-stone setting: A three-stone setting is a ring design with one centre stone and a gem on each side of it, the same size or smaller, so three stones sit in a row.

W

White gold: White gold is gold mixed with whiter metals, such as palladium or nickel, and often coated with a thin layer of rhodium so it looks bright white.