Gold:

 CPM is the common source of where jewellers buy their metals from. CPM stands for Cape Precious Metals are based in Johannesburg, Durban and Port Elizabeth but the head office is in Servicing Western Cape and Namibia. Gold in jewellery is determined by "Karat" which is the measurement of purity of gold alloyed with other metals. Gold varies in colour as yellow gold(pure gold), White gold(yellow gold with palladium and nickel), Rose Gold(yellow gold with copper).Personally my favourite gold is Rose Gold. 

Different colour Gold

The different alloys are defined as 24kt:pure gold with no other metal added, 18kt: contains 75% gold and 25% copper or silver, 14kt: contains 58.3% pure gold and 41.7% copper, 9kt: 37.5% pure gold and 62.5% copper. in the CPM price listing the fine gold are seen with elements(alloy) Y R which is Yttrium and Rhenium, W(%PD) is gold with an alloy of Tungsten and the percentage of Palladium added, W(PD/PT), is gold alloyed with Tungsten and palladium and platinum, W(Ni) is gold alloyed with Tungsten and Nickel. 9Kt gold is seen with Nickel and Nickel free as Nickel is only added to give metals its particular properties, for instance nickel is added to white gold to whiten the gold. 

The different types of gold solders found are usually a karat or two lower than the gold pieces being soldered. It also comes in Hard, Medium and Easy solder. In the CPM price list it is seen with the periodic elements indicating those are the elements added to the solder that are EMHEE Y(Easy, Medium, Extra Easy Yttrium), EM Y(Easy, Medium Yttrium), M R(Medium, Repair). 

Gold Solder