Gold properties
Color:
Golden, butter yellow with a metallic lustre or shine.
Hardness: 2-3
Chemistry: Element, AU
Specific Gravity: 15.5-19.3
Crystal system: Isometric
Crystal Habits:
nuggets, grains, wires, dendritic and arborescent
crystal clusters.
When you buy your next gold bracelets, it is good to think a bit about what you are purchasing. Remember that Gold is one of the most beautiful elements on earth. Because it is so malleable, it can be easily hammered into thin sheets. Its ductile property allow it to easily be stretched into a very thin wire. These special attributes, make gold very useful for jewellers to work with and produce beautiful jewellery. It is also minted to produce Gold coins.
Gold is rare, but can be found all over the world, in either form of nuggets, flakes or dust. The larger deposits are called quartz conglomerates and account for around the 20% of the world´s Gold. The largest deposits are found in South Africa.
Deposits of Gold are also collected in rivers. After mining or prospecting, gold is extracted from deposits by processing it with sodium or potassium cyanide to remove other materials. When you show off your gold bangle bracelets, remember what it cost to bring it all the way to you!
To keep cost down and make Gold harder, sometimes it is alloyed with other metals like copper or silver. When mixed with these metals, Gold changes its color. If Iron is present, its called Blue Gold. When missed with more Silver than Copper, its Green Gold. Pink or Rose Gold, consists of 50% gold, 45% Copper and 5% Silver. Rose Gold makes wonderful gold charm bracelets. To make white gold, they mix Nickel, Zinc, Copper. So this new white gold bracelet you just purchased is a mixture of good metals.
Measures
Experts calculate the amount of Gold in an Alloy by the Karat system.
24kt.: 100% Gold-very soft
18kt.: 75% Gold-will not tarnish; softer than 14kt., but with a deeper color
14kt.: 58.33% Gold-will not tarnish
12kt.: 50% Gold
10kt.: 41.6% Gold; less than 10kt. cannot be called Gold in the US or 9kt. in the UK.
Gold wont dissolve in Aqua Regia, so this acid is used to determine if a metal is Gold.
The higher Karat Gold jewellery is more resistant to tarnishing.
Techniques used in Goldworking
Electroplating: Electrically coating another metal with gold.
Filigree: Creating a decoration with Gold wire into an object by welding it in.
Granulation: Forming shapes on embossed metal by using very small balls of Gold .
Interassile: Piercing designs into gold thin sheets.
Repoussé: Hammering a relief in a negative mold into the Gold sheet
Rolled Gold: Gold is laminated onto a less expensive sheet of metal, heated till they are joined together and then rolled into a workable thin sheet.
Nowadays you can buy a very sofisticated 14k gold bracelet for a decent price in many online jewlery stores.
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