Platinum Jewelry Appraisal, Quality Markings, Alloy Composition

Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. It Is in Group 10 if the periodic table of elements. A dense, malleable, ductile, precious, gray-white transition metal. It is resistant to corrosion and occurs in some nickel and copper ores along with some native deposits. It is used in jewelry, laboratory equipment, electrical contacts and electrodes, platinum resistance thermometers, dentistry and catalytic converter.

CHARACTERISTICS OF PLATINUM

• Is silvery-white in appearance, lustrous, ductile and malleable
• It does not oxidize at any temperature
• Does not tarnish and resist corrosion
• Insoluble n hydrochloric and nitric acid but dissolves in equal regia to form chloroplatinic acid.
• It is more precious than gold and silver
• It is harder than gold and silver, so it outwears them and it not as easily scratched. Its hardness is 4 to 4.5 on MOH’s scale of hardness about the same as iron. When Platinum is mixed with iridium or ruthenium, it becomes much harder and therefore more suitable for jewelry weat.
• It is heavy and dense compared with other metals. It is approximately twice as heavy as silver.

PLATINUM QUALITY MARKINGS

The Platinum standard is different from other metals.  Gold purity is familiar subject: 24 karat gold equal 99.99% pure gold, 18 karat is 75% pure and 14 karat is 58% pure. In the platinum world, 1,000 parts of platinum equal 100%. All other alloys are derived from these 1,000 parts.

Percentage	Common Quality Marks	Alloy Composition
99% Platinum	Platinum Plat Pt Pt1000 Pt999	999 parts per thousand platinum and 1 part other metal
95% Platinum	Platinum Plat 950Pt 950Plat Pt950	950 parts per thousand platinum and 50 parts other metals (usually ruthenium, iridium, cobalt, copper, tungsten, palladium or a combination of cobalt and copper
90% Platinum	900Pt 900Plat Pt900 IRIDPLAT 10% IridPlatinum	900 parts per thousand platinum and 100 parts other metals (usually iridium or palladium) IRIDPLAT is 900 parts per thousand platinum and 100 parts per thousand iridium
85% Platinum	850Pt 850Plat Pt850	850 parts per thousand platinum and 150 parts other metals (usually palladium)
80% Platinum	850PT 850Plat Pt850	800 parts per thousand platinum and  200 parts other metals.
75% Platinum	750Pt 750Plat Pt750	750 parts per thousand platinum and 250 parts other metals.
58.5% Platinum	585Plat 415Pall	585 parts per thousand platinum and 415 thousand platinum.

How to Appraise Platinum

1. Platinum should have quality markings as to its fitness Pt1000; Pt900; Pt850; Pt800; Pt750; Pt700; Pt500
2. Do not accept articles without quality markings even if it is Platinum (no basis for valuation when pawned.)
3. Platinum usually have uneven surfaces, not shiny and lustrous.
4. Shows deformation due to its malleability.
5. No reaction when applied with Nitric acid
6. Heavy and usually have diamonds.

Other Factors to Consider in Appraising Platinum

METAL	COLOR	LUSTER	WEIGHT	CHARACTERISTICS/USAGE
Platinum	Grayish	Dull	Heavy and dense	Malleable and ductile With markings as to fineness No reaction on Nitric Acid Harder than silver
Titanium	Gray	Shiny	Lightweight	100% hypoallergenic Hard metal Cannot be revised Used as aircraft metals for low weight Cannot be resized Does not tarnish and corrode
Silver	White	Lighter than platinum		Malleable Corrosion-resistant Does not react to chemical but react to sulfur (present in the air) Tarnish due to sulfur Usually stamped as silver No reaction on Nitric Acid
Stainless Steel	White	Shiny	Lighter than platinum	Usually stamp as stainless steel No reaction to Nitric Acid Does not stain due to chromium-rich in oxide film