The weight of a piece of gold helps determine its value. Gold and silver are commonly weighted in the troy system of weights. Troy weight is a system of measurement for precious metals, precious stones etc. where a pound is equivalent to 12 ounces. The name “Troy” is derived from Troyes, France, the city where the system was first used.

Grams (g) and pennyweights (dwt) are the units of weight most often used in the jewelry and refining industry.

WEIGHT CONVERSION TABLE

1 gram (g)	=	0.643 dwt	=	0.0032 oz t
1 pennyweight (dwt)	=	1.555 g	=	0.05 oz t
1 troy ounce (oz t)	=	31.103 g	=	20 dwt

The purity of gold is defined by the term karat. Gold purity is described by the amount of pure gold in parts per 1000. For example, a gold ring containing 750 fine gold has 750 parts (75.0%) gold and 250 parts (25.0%) of other metals.

GOLD KARAT INFORMATION CHART

US Gold Markings	Parts	Gold Percent	EUR Gold Markings
9 kt	9 / 24	37.50%	375
10 kt	10 / 24	41.67%	416
12 kt	12 / 24	50%	500
14 kt	14 / 24	58.33%	583 or 585
18 kt	18 / 24	75%	750
22 kt	22 / 24	91.67%	917
24 kt	24 / 24	99.99%	999 or .99999