A to Z of Diamonds Glossary

Diamonds Index

Round Brilliant Cut Diamond

P1, P2, P3, Piqué, First, Second, Third	Clarity grades of diamond in descending order, The American equivalents are I1, I2, I3. In a piquéd stone, the inclusion or inclusions would be visible to the naked eye.
Palladium	Important jewellery metal, used in high quality alloys of platinum and white gold.
Panther, Pink	The Pink Panther was the name of a fabulously valuable diamond which the jewel thief of the same name was trying to steal in the film "The Pink Panther starring Peter Sellers as Inspector Clouseau.
Parcel, Parcels	Paper envelopes for diamonds, and also, importantly, the diamonds they contain. Many diamonds are traded by the parcel, rather than the buyer being permitted to pick the best.
Parcel Price	A per carat price for buying an entire diamond parcel without selection. Sometimes a buyer is permitted to reject a small number of stones.
Paste	Glass used as imitation diamond. Also diamond grit or powder supplied or used in paste form as an abrasive for cutting and polishing any material including other diamonds. The paste may be made with oil or any other binder to facilitate application and adhesion to lapping wheels etc.
Pavé	From French, literally paved. Diamonds are other gemstones set in such a way that they substantially cover a surface of a piece of jewellery.
Pavilion	The lower part of a diamond, below the girdle.
Pavilion Angle	The angle between the main pavilion facets and the girdle. In diamond cutting and proportion, this is the single most important dimension, and should be around 40.75° to 41°.
Pavilion Facet	Any of the facets on the pavilion of a diamond, but usually referring to the main pavilion facets, as distinct from the lower girdle facets.
Peg	Brummy (Birmingham) word for claw as in gem setting.
Pegasus Overseas	Pegasus Overseas Limited, as subsidiary of General Electric market HPHT colour improved diamonds which they claimed were almost undetectable, causing a near panic in diamond markets when announced in March 1999.
Pendant, Pendants	A piece of jewellery designed to dangle or hang. Often diamond set.
Percentage	There are various ratios usually expressed as percentages which give indications of the accuracy of a diamond's proportions. Also a dealer's mark up.
Perfect, Perfection	Only D colour and flawless diamonds should be described as perfect. It is our view that perfection is illusory or elusive, as "perfect" diamonds viewed under 20 times magnification instead of 10 times, would probably reveal tiny features or imperfections.
Phonon, Phonons	The quantum of acoustic or vibrational energy, considered a discrete particle and used especially in mathematical models to calculate thermal and vibrational properties of solids.
Phosphorescence	Some diamonds and other gemstones and minerals continue to glow or emit visible light for a period of time after exposure to visible, ultra-violet or other light, after the light source has been removed.
Photoluminescence	The emission of visible light by a diamond due to the incidence of light of a different wavelength, including fluorescence and phosphorescence.
Pick	A "pick" is when a buyer is permitted by the seller to select one or more diamonds from a parcel.
Picking Price	Normally a higher price is charged to a buyer wishing to take one or more selected stones from a parcel, this is known as a picking price.
Pink	One of the rarest and most desirable colours for diamond.
Pink Panther	The Pink Panther was the name of a fabulously valuable diamond which the jewel thief of the same name was trying to steal in the film "The Pink Panther starring Peter Sellers as Inspector Clouseau.
Pinpoint, Pinpoints	Tiny inclusions, of pinpoint size, sometimes numerous.
Pipe, Pipes	A diamondiferous area composed of kimberlite, sometimes raised above softer surrounding rock, originally of volcanic origin as a lava flow.
Piqué	From French "prick", a needle or other inclusion in a diamond. First piqué (P1) is a clarity grade, the American equivalent is I1.
Pit	Diamond mine. Surface mark on diamond.
Presence	The presence or absence of colour, inclusions and other features considered when appraising and grading diamonds.
Platen, Baltzar von	Swedish scientist who was the first to synthesize diamond in 1953 while working for ASEA.
Platinum	Silvery gray precious metal often used for setting or mounting high quality diamonds as jewellery.
Pochette	A sealed plastic packet containing a diamond or diamond.
Point	A weight of one hundredth of a carat, written as 0.01 cts. The name of an old basic cut. Any sharp meeting place of three or more facets, such as a corner, or a closed culet; forms a weak point in polished diamonds, as a sharp blow to a point could easily cause the diamond to cleave (break).
Polish, Polished, Polishing	In diamond manufacturing, polishing can refer to the grinding of facets onto a partially made rough diamond, but more particularly the later stages of brillianteering.
Polished Girdle	A girdle which had been finely ground to a polished finish instead of the older and simpler matt finish left by bruting.
Polish Lines	Faint surface lines visible either as a result of imperfect polishing, or of grain lines in the diamond.
Polish Mark	A "burn mark", and area of slight cloudiness on the surface of a diamond caused by allowing it to become too hot when grinding or polishing it.
Portuguese Blue	A large and famous diamond owned by the Smithsonian Institution, which is neither Portuguese nor blue.
Powder	Usually referring to diamond powder used for polishing diamonds or other materials.
Precious	Having high or relatively high value, usually applied to gemstones, particularly the "big four", diamonds, emeralds, rubies, and sapphires, but also includes black opal.
Price, Prices, Pricing	Diamond pricing is extremely variable. Comparison pricing requires consideration of all aspects of quality.
Princess	A square or near square (oblong) diamond, which has been facetted in a brilliant cut style rather than a step cut.
Production	Current world production of gem diamonds is about 30 million carats (6,000 kg) of cut and polished stones annually, and over 100 million carats (20,000 kg) of diamonds are sold for industrial use each year. In 2003, this constituted total production of nearly US$9 billion in value.
Prong	American word for claw, as in gem setting.
Proportion	The consideration of the overall shape of a diamond taking each part in relation to all other parts. An important quality element for diamonds.
Proportionscope	A proprietary piece of equipment for assessing, demonstrating, and measuring the proportions of diamonds, and comparing them with ideal.
Purity	Another word for clarity.
Purple	A very rare and attractive fancy diamond colour.

There are currently over 600 entries in this table.
Over 90 of them have page links to a page on this site. Eventually, we intend to add a more complete description for most entries, each on its own page. Please watch this space!