Platinum Gold and Silver Precious Metals

PRECIOUS METALS

Metals: Gold · Platinum · Silver
Charts: Gold Standards, Properties, Troy Weight
 

Noble Metals

Noble Metals: Resistant to rust and corrosion caused by oxygen or acids.

Ferrous - Iron & Steel.

Non-Ferrous further divided into 3 main subgroups.

  1. Precious Metals - silver, gold, platinum.
  2. Base Metals - copper, aluminum, lead, tin, nickel and zinc.
  3. Alloys - brass, bronze, pewter, nickel, silver, solder, sterling silver, karat gold, Monel Metal (68½% nickel, 29% copper, 1% iron, 1% manganese, silicon, sulfur and carbon), nichrome (80% nickel, 20% chromium).

Alloys

  • Binary alloy - contains 2 metals
  • Ternary alloy - contains 3 metals
  • Quarternay alloy - contains 4 metals
  • Quinary alloy - contains 5 metals

Gold

The earliest craftsmen used gold. Gold has no oxides and is the only metal not affected by the oxygen in the atmosphere. No other metal surpasses gold in malleability. Malleability is the ability to be beaten or rolled in any direction without cracking or breaking. And it's ductility, its ability to be drawn into fine wire, the fineness of hair. Descending order of ductile metals:
Gold, Silver, Platinum, Iron, Copper, Aluminum, nickel.

Alloys of Gold

Copper, Silver, Nickel, and Zinc

  • White gold contains:
      25% platinum or 12% palladium.
  • Green Gold contains:
      30 - 40% silver or silver + cadmium and zinc.
  • Yellow Gold contains:
      silver & copper.
  • Red Gold contains:
      a higher percentage of copper.

Allergic to Gold?

Copper,silver, nickel or zinc is the culprit. Allergic reactions and skin discolouration by gold is caused by skin secretions or perspiration containing chlorides. When perspiration comes into ABOUT with the copper and silver alloys in gold it sulfides producing dark-coloured salts, copper sulfate or silver chloride.

Quick fixes like painting a clear coat to protect the skin offers temporary relief. If you're not allergic to rhodium, consider rhodium plating your silver. Eighteen karat gold is a better choice as is 18 karat white gold. Changing to pure 24kt gold or platinum will usually eliminate the problem entirely.

Platinum

Six elements make up the Platinum family.

Platinum: discovered in the 16th century. Melting point 3224.3°F. Specific gravity over 21. Greyish white in colour. Used in electric wires, ABOUT points, dentistry and photography. Valued in X-ray and tube manufacture, because it's the only metal that will fuse to glass without breaking the glass. Alloyed with Rhodium and Palladium and used for jewellery. Alloys containing 5 and 10 % ruthenium or iridium are called medium hard and hard platinum.

Rhodium: discovered in 1804. Melting point 3560°F. Specific gravity of 12. Used almost extensively for electroplating.

Palladium: discovered in 1804. Melting point 1652°F - 2831°F. Specific gravity of 12. Used in scientific instruments and in its pure state for electroplating.

Ruthenium: discovered in 1845. Melting point 3560°F. Specific gravity of 12. Bluish white in colour. Has no commercial value.

Osmium: discovered in 1804. Bluish white in colour. Specific gravity over 21. The heaviest metal known. Associated with Iridium in alloys.

Iridium: discovered in 1804. Specific gravity over 21. Silvery white in colour. Used in electrical apparatus and ABOUTs, and for standards of weights. When found combined with Osmium, its a natural alloy called Osmiridium.

Platinum jewellery is so expensive!

It is extremely rare. Platinum is pure, it is not alloyed with less expensive metals. Platinum is 60% more dense than gold, so it is more expensive in just its bulk weight. Platinum is considerably heavier and far stronger than gold. Due to its unique working properties, Platinum requires a Master PlatinumSmith. And a working environment that is exclusively devoted to the creation of fine platinum jewellery. That means, a separate work area complete with its own tools. With all of these factors considered, the price of a finely crafted piece of Platinum Jewellery is worth the investment and can be treasured for several generations. Platinum may cost as much as five times more than gold.

Silver

Esteemed for centuries. Used in electroplating, manufacture of photographic film and dentistry. Second only to gold in malleability and ductility. Fine silver is 999.0 parts per thousand fine. High fine silver is 999.5 or higher. Fine silver is used in enameling because of the absence of oxides formed by copper in alloys. The standard alloy of sterling silver is composed of 925 part pure silver and 75 parts pure copper. Mexican silver is alloyed with .950 parts silver and the remainder in copper. Tarnish on silver is produced by sulfuric oxides in the atmosphere and by certain foods or body salts.

Gold Content

American Standard

24kt = 100% · 22kt = 91.67% · 20kt = 83.33%
18kt = 75% · 14kt = 58.33% · 10kt = 41.67%

European Standard

750=18kt · 585=14kt

Metal Properties

Metal
Name
Chemical
Symbol
Specific
Gravity
Atomic
Weight
Moh's
Hardness
Melting
Point
Platinum Pt 21.45 195.23 4-4½ 3224.3
Palladium Pd 12.00 106.4 4-4½ 2831
Gold Au 19.32 197.2 2½-3 1945.4
Silver Ag 10.50 107.88 2½-3 1760.9

Troy Weight

24 grains (gr.) = 1 pennyweight (dwt.)
20 dwt = 1 Troy ounce = 31.103 grams (gm.)

© 1997 Contents & Graphics All Rights Reserved by Nanami Laskey © 2005 AGStudio