Gold won’t tarnish, rust, or corrode, and though it’s very strong, it is also the most malleable of all metals.
Pure gold is too soft to withstand the stresses of daily wear, so it is alloyed with a mixture of metals like silver, copper, palladium, and zinc to give it strength and durability. The amount of gold content determines the purity and overall carat.
9ct gold has 375 parts per 1000 and is hallmarked 375
18ct gold has 750 parts per 1000 and is hallmarked 750
Gold in its natural state is yellow so to make an 18ct White gold ring 75% of gold is mixed with 25% of white metal usually palladium or other platinum family metals to give it a white look. A natural white gold alloy will have a warm yellow appearance next to a white platinum ring.
18ct white gold is usually plated with Rhodium another metal from the platinum family. This coating will give the item a white appearance. This process can be re applied very easily to restore the item back to its original colour.
One of the most vivid descriptions of a medieval goldsmith’s workshop was given by Alexander Neckham. His lively description may reflect his personal observations of goldsmiths at work in Paris in the late 12th century. In his words:
“The goldsmith should have a furnace with a hole at the top so that the smoke can get out. One hand should govern the bellows with light pressure and with the greatest care so that the air pressed through the nozzle may blow upon the coals and feed the fire. Let him have an anvil of extreme hardness on which the iron or gold may be laid and softened and may take the required form.They can be stretched and pulled with the tongs and the hammer. There should also be a hammer for making gold leaf, as well as sheets of silver, tin, brass, iron or copper.
The goldsmith must have a very sharp chisel with which he can engrave figures of many kinds on amber, hard stone,marble, emerald, sapphire or pearl.He should have a touchstone for testing and distinguishing between iron and steel. He must also have a rabbit’s foot for smoothing, polishing and wiping the surface of the gold and silver. The small particles of metal should be collected in a leather apron.
He must have small pottery vessels and cruets, and a toothed saw and file for gold as well as gold and silver wire with which broken objects can be mended. He must also be as skilled in engraving as well as in bas relief, in casting and as well as in hammering.His apprentice must have a waxed table, or one covered with clay, for portraying little flowers and drawing in various ways.
He must know how to distinguish pure gold from latten and copper, lest he buy latten for pure gold. For it is difficult to escape wiliness of the fraudulent merchant.”