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P Edit 39 terms found

P
A grade in GIA’s Color Grading System…. in the middle of the “Very Light Yellow” category.
Padparadscha
Derived from the Sinhalese term for “lotus flower,” padparadscha refers to a lush pink and orange sapphire resembling the color of the lotus. Padparadscha is also sometimes used to refer to other types of gemstones, such as topaz and tourmaline, with this unique coloration.
Paraiba
A rare copper-bearing tourmaline with an intense blue or blue-green color, first found in the state of Paraiba in Brazil in 1989. There have been recent finds in Nigeria and Mozambique of similar material, and the term “paraiba” is now used to refer to all examples of this copper-bearing tourmaline. See also Copper-bearing.
Parcel Paper
Also called diamond papers. Folded sheets of paper used to contain polished or rough diamonds. On the outside of the paper are many different numbers- such as stock number, clarity, color, carat weight, shape, supplier, cost, etc. Contrary to what you see in the movies…. diamonds are not kept in big piles in boxes and trays… they are kept in papers.
Paste
A term for glass imitation gemstones.
Patina
A sheen which develops on the surface of platinum jewelry through continued wear.
Pave
(pah-VAY) A style of setting small stones very tightly together, as in a pavement or paved with diamonds. Most commonly seen with diamonds, but may be used with any stone.
Pavilion
The lower portion of a gemstone that begins just below the girdle.
Pavilion Angle
The angle measured between the girdle plane and the pavilion main facet.
Pavilion Main Facet
Eight, four sided facets of a Round Brilliant Cut diamond that meet at a point to form the culet.
pc
Abbreviation for “per carat” pricing…. expressed as $750pc.
Pear Cut
Resembling a pear or teardrop, this fancy cut is rounded on one end and pointed on the other.
Pedometer
The first self-winding pocket watch design, invented by Abraham-Louis Perrelet in 1770. Thus named after the source of its power (i.e. a weighted lever that jerks as a man walks).
Perfect
This term has been so flagrantly misused in the sale of diamonds that many jewelers avoid its use entirely. The American Gem Society also prohibits its use by its members. The Federal Trade Commission considers it an unfair trade practice to use the word “perfect”, or any other word, expression or representation of similar import, as descriptive of any diamond that discloses flaws, cracks, carbon spots, clouds or other blemishes or imperfections of any kind, including inferior color and make, when examined by a trained eye under a corrected diamond eye loupe or other equal magnifier of not less than ten power.
Perpetual Movement
Another term for an automatic or self-winding movement with a winding rotor that travels a full 360 degrees.
Phenomenal Gems
Gems that display unusual optical properties such as color change, chatoyancy, asterism or iridescence.
Pigeon’s Blood
Refers to the most prized color of red in rubies. Pigeon’s blood red is thought to be a pure red with a hint of blue. It is associated most with rubies from Burma, though any ruby could be this color.
Pinpoint
A pinpoint is a extremely small included crystal inside of a diamond. A grouping of pinpoints is called a “cloud”. A cloud can appear as a hazy area in the diamond. A single pinpoint can change a diamond clarity grade from an Internally Flawless to a VVS1.
Pipe
The remains of an ancient volcano. Diamond bearing magma (kimberlite) had made its way to the surface via a weak spot in the earth’s crust. The volcanic mountain that was formed is then eroded away from rain and all that is left is the pipe. Open pit mining is done on top of the pipe and a vertical shaft is sunk next to the pipe with horizontal tunnels dug into the pipe. Kimberlite pipes have been found in Africa, Canada, Russia, Arkansas, Australia, and elsewhere.
Pit
A tiny opening on the surface of a diamond, often looking like a white dot.
Pivot
The turned down part of an arbor. This part commonly projects through the hole in watch jewels.
Plate
The portion of the movement which supports the bridges and other plates.
Platinum
A rare precious metal used in jewelry. Platinum is naturally white and is favored for many ring settings because of its durability.
Pleochroism
The ability of certain gems to display two or more colors when viewed from different angles. This is a term also used for Dichroism and trichroism.
Plotting Diagram
A diagram used on some Diamond Grading Reports that illustrates the facets of a diamond and the approximate location and type of internal and external characteristics.
Point
A trade term used to describe the weight of diamonds. One point is equivalent to one-hundredth of a carat. For example, a 1/4 carat diamond, equals 0.25ct., equals 25 points.
Pointer
Term used to describe polished stones under a carat. For example, a 37 pointer (0.37ct.).
Polish
The smoothness of the surface of a diamond which shows no visible wheel or burn marks. Polish is regarded as one of the indicators of the quality of as diamond’s cut; it is graded as either Ideal, Excellent, Very Good, Good, Fair, or Poor.
Polish Lines
Tiny parallel lines left by irregularities in the diamond cutting wheeel’s surface.
Polish Mark
Surface clouding caused by excessive heat (also called burn mark, or burned facet), or uneven polished surface resulting from structural irregularities.
Polished Girdle
A girdle that has been lapped or polished to yield a uniform, highly reflective surface.
Polishing
In diamond fashioning, it is used to include both lapping, or blocking, and brillianteering, as well as the production of any facet; the final operation in fashioning a diamond, usually done with diamond powder on a horizontal disc, or lap, against which the diamond is held in a dop.
Poor Cut
A inferior cut diamond that can be either cut too deep or too shallow which will lose or leak light through the side or bottom resulting in less brilliance and value.
Precision
Term used by Rolex to describe their watch movements which had not received a timing certificate, thus were not rated as chronometers.
President
This nickname is often used to describe the Rolex Day-Date models, since one was given to then President Dwight D. Eisenhower in 1956 to celebrate his re-election, and nearly every President since Franklin D. Roosevelt has worn one. However, the name ‘President’ is officially only used to describe the bracelet style featured on the Day-Date model.
Princess Cut
A square or rectangular-shaped modified brilliant cut diamond.
Prong or Claw Setting
A setting style that uses 4 or 6 small fingers of metal that hold a diamond in place. Each metal prong is individually pushed into place to hold the diamond securely.
Proportion
The proportions of a diamond are very important, so that the maximum amount of light be reflected off and out of a stone. Proportion is the relationship between the angles of the facets of the crown and pavillion.
Proportion Scope
A device that combines lenses and movable mirrors to project the silhouette of a diamond onto a screen. Diagrams and scales are printed on the screen which facilitates the analyzation of the proportions of round brilliant cut diamonds, as well as fancy shaped diamonds.