FAQ about Gold

Why is gold measured in karats?

This stems back to ancient times in the Mediterranean / Middle East, when a karat became used as a measure of the purity of gold alloys (see next Question 5). The purity of gold is now measured also in terms if fineness, i.e parts per thousand. Thus 18 karats is 18/24th of 1000 parts = 750 fineness.

What is a Carat?

A Carat (Karat in USA & Germany) was originally a unit of mass (weight) based on the Carob seed or bean used by ancient merchants in the Middle East. The Carob seed is from the Carob or locust bean tree. The carat is still used as such for the weight of gem stones (1 carat is about 200 mg). For gold, it has come to be used for measuring the purity of gold where pure gold is defined as 24 carats. How and when this change occurred is not clear. It does involve the Romans who also used the name Siliqua Graeca (Keration in Greek, Qirat in Arabic, now Carat in modern times) for the bean of the Carob tree. The Romans also used the name Siliqua for a small silver coin which was one-twentyfourth of the golden solidus of Constantine. This latter had a mass of about 4.54 grams, so the Siliqua was approximately equivalent in value to the mass of 1 Keration or Siliqua Graeca of gold, i.e the value of 1/24th of a Solidus is about 1 Keration of gold, i.e 1 carat.

How much does a gold bar weigh?

Gold is made into a large number of different bars of different weights. The most well known are the large 'London Good Delivery Bars' which are traded internationally. These weigh about 400 Troy Ounces, i.e. 12.5 kg/ 27 lbs. Each. Others are denominated in kilogram's, grams, troy ounces, etc. In grams, bars range from 1 g up to 10 kg. In troy oz, from 1/10 tr.oz. up to 400 tr.oz.. Other bars include tola bars and Tael bars.