Monday, November 30, 2009
Varieties of Gold
Before you go to pick your gold, it makes sense to know the types of gold there are and how they are used. “Gold Filled” and “Gold Overlay” refers to a layer of at least 10 karat gold that has been permanently bonded by heat and pressure to one or more surfaces of the support metal, and then rolled down or drawn to a prescribed thickness. The karat gold must be at least one-tenth of the total weight.
Gold plate implies that a layer of plating of 10 karat gold or better has been bonded to a base metal. The karat gold content may be less than one-twentieth, but it must be properly identified by weight in terms of total metal content. Gold leaf is gold plating that has been pounded and applied by hand.
Pure gold is bright golden yellow in colour. Other metals are alloyed with gold to give strength to the gold.
Rose gold – Rose gold is slightly reddish shade. This colour change is due to mixing of copper.
White gold – It looks pale because it is almost silver coloured gold. It causes due to nickel.
Green gold – Green gold is slight greenish in colour. It is due to mixing of copper and silver.
Blue gold – Blue gold with slight bluish shade. This is caused by iron.
The purity of gold metal depends upon the percentage of mixing of other metals (alloyed). The high karat measurement is undesirable for jewelry because it is bendable and soft. The measurement is gold in international is in troy ounce.