SILVER 
Advantages
Silver is malleable which makes it easy to use in many different types of jewellery. It is not scarce and thus more affordable than other precious metals. It is easy to resize non-gemstone silver rings.
 
Disadvantages
Silver tarnishes easily and often and thus requires more frequent care and cleaning. Pure silver is too soft to be used in jewellery. Because of its properties when heated, it can be difficult to resize silver rings with gemstones for fear of damaging the stone.
 
Alloying
Sterling silver is 92.5% silver and 7.5% copper by definition and should be marked "sterling," "925," or "ster." Sterling silver is typically what people mean when they talk about silver jewellery.
 
 
GOLD
Advantages
Gold is highly malleable which enables it to be crafted into many styles and sized fairly easily. It also comes in a variety of colours and does not tarnish easily.
 
Disadvantages
Gold is more expensive than almost all other precious metals. Its softness can also result in scratching and denting.
 
Alloying 
The purity of gold is measured in carats. 
Pure gold is 24 carats, but 24 carat gold is too soft to securely hold a stone. So gold is alloyed with other metals such as silver, copper and zinc to make it sturdier. Typical measurements for alloyed gold are 18 carat (75% gold), 14 carat (58.3% gold), 10 carat (41.6% gold) and 9 carat (37.5% gold).

 

United States

Europe

Percent Gold

24 carat

1000

100%

18 carat

750

75%

14 carat

585

58.3%

10 carat

417

41.7%

  9 carat

375

37.5%


Colours 
Yellow gold 
This gold is non-corrosive and sturdy. Diamonds set in yellow gold benefit from colour contrast, and slightly tinted stones can appear brighter.
 
White gold
The shiny silver hue of white gold makes it look like platinum, but is virtually non-tarnishing.
 
Rose gold 
The gold is alloyed to bring out deeper pink accents. 

Gold Filled or Gold Overlay
A layer of gold bonded to the surface of a support metal. The gold must be at least 10% of the total weight.

Gold Plate
Similar to overlay, the gold content may be as little as 5% of the total weight.

Gold Leaf
A very thin layer of gold is applied by hand to the surface of an item.
 
PLATINUM
Advantages
Platinum has highly durability, heavy weight, high value, minimal threat of tarnishing; and because of its strength, it provides a sturdy grip of diamonds and gemstones. Additionally, thanks to its natural purity, it is hypoallergenic.
 
Disadvantages
The two primary drawbacks are its very high price (much higher than gold) and its strength that makes it more difficult to resize.
 
Alloying
Platinum is naturally alloyed with as many as five other heavy metals that are extremely similar in chemistry and weight. Unlike gold, platinum is sold in its nearly pure form and should be stamped with a symbol to reveal its purity, typically "900 Plat" (90% pure) or "950 Plat" or "Plat" (95% pure).