pique Pirie Diamond Pitt Diamond
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Sunday, 23 September 2007

pique (pee-kay"). From the French meaning pricked. A term used by some importers as an imperfection grade. The original use of the word was confined to those stones that had tiny, difficult-to-find inclusions. It has been used with increasingly poor stones until 1st, 2nd and 3rd pique grades now sometimes fit in between or replace slightly imperfect and imperfect. Some importers still use the terms 1st, 2nd and 3rd pique for grades just below flawless or per­fect, and others for categories of the imperfect grade. Sometimes ab­breviated RK. See clarity grade; rk.

Pirie diamond. A one-carat blue di­amond bought by Edwin W. Streeter in Paris in 1877. Streeter believed that it came from the recutting of the French Blue. Its present whereabouts is unknown and no other historical details are available.

pit. An indentation on the surface of a diamond. It may be caused by a blow or by a knot being pulled out from the surface during the polishing operation. A fairly large indentation is usually called a cavity; a minor one, a nick. See percussion mark.

Pitt diamond. See recent diamond.

P.K. An abbreviation often used for pique. See pique, clarity grade.

placer. Alluvial deposit of heavy minerals concentrated on the surface by moving water or air. Usually a loose mass of gravel, sand, or similar material resulting from the crumbling and erosion of solid rocks containing valuable minerals such as gold, platinum, tin, Diamonds, and other Gemstones. In most cases the gems or metals can be collected by washing or amalgamation without milling. See alluvial

planned leakage. See leakage.

Platberg diamond. Although dia­monds have been reportedly found in Africa prior to 1860, one of the first documented stones is the Plat­berg diamond. Its occurrence is re­corded in the daily diary of the Pniel Station of the Berlin Mission Society. This 5-carat stone was found by a na­tive in 1859 on the riverbank of the Vaal River near Platberg, Republic of South Africa. It was later purchased by a Mission priest for £5. Its present whereabouts is unknown.

Pliny the Elder. A Roman naturalist and one of the earliest authors to de­scribe the diamond (77 A.D.): "a