There are a variety of metals choices available for jewelry. Whether you like the allure of platinum or the range of options with the classic gold, you will find a number of stylish pieces, sometimes even combining the two metals. Today, alternative metals like sterling silver, titanium, and stainless steel give you additional options in look, strength, price, etc. Each choice has its own qualities, so base your choice on the ones that you value most.
Precious metals are weighed in "Troy Ounces" or fractions there of. Two very common methods are Pennyweight (dwt) or Gram (g) weight. There are 20dwt to one troy ounce, 5 dwt to 1/4 troy ounce, etc. (very easy). There are 31.1035g to one troy ounce, a little more confusing as 1/4 troy ounce would be 7.7759g.
Here in the US we commonly use the Avoirdupois Ounce to weigh letters, meats, etc. This ounce only has 28.3495 grams, much different than a Troy Ounce. We wouldn't suggest weighing your precious metals on a postage scale unless you completely understand the conversion to troy weight.