NOBLE METALS: GOLD, SILVER, & PLATINUM

Of more than 90 elements that make up the Earth's matter, only three of them are considered as noble metals. These three metals are Gold, Silver, and Platinum. The term noble in chemistry means metal which resists oxidation and corrosion.

Among the noble metals, gold reigns supreme. It has awoken love, desire, and greed. Empires have been building on gold, and civilizations have been destroyed by it.

Gold - It can be dissolved with hot chlorine bleach, selenic acid in water, a hot cyanide solution, and a mixture of nitric and hydrochloric acids, thus Gold is very durable. Gold is wonderfully workable because no other metal is more ductile or malleable. One ounce can be drawn out into a wire thread of more than 50 miles long. 

Noble Metals Toronto

Pure gold is expensive and soft; metalworkers alloy gold with at least one other metal. Karat refers to the relative fineness of gold in the alloy. It tells the number of parts, by weight, of gold in 24 parts of alloy. The gold content of an alloy is indicated by Karat stamping.

KARATPARTS GOLD GOLD PURITYFOREIGN STAMPING
6K6/2425.0%250
8K8/2433.3%333
9K9/2437.5%375
10K10/2441.7%417
12K12/24500%500
14K7/1258.3%583/585
15K5/862.5%625
18K3/475.0%750
20K5/683.5%833
21K7/887.5%875
22K11/1291.6%916
24K24/2499.9%999

SILVER - has drawbacks, it tarnishes easily, and if you neglect it, it will turn almost black. Silver is less durable than gold or platinum, but is a more solid heat conductor which makes it harder to work with than other metals. Silver has a nice feel to it and takes a high polish.
STERLING SILVER - must be at least 92.5% pure (The rest is usually copper)
THE PLATINUM GROUP - Platinum is rarer than gold. Its grayish-white color and non-tarnishing quality makes it a preferred setting for colorless diamonds. Platinum occurs in association with other rare metallic elements known as the platinum group of metals. Jewelry platinum is usually 90% platinum and 10% iridium.