You must first find the spot price of gold (per troy ounce) in your country, then convert to grams.
Thus, if the spot price of gold is $900 per troy ounce and there are about 31.10 grams in a troy ounce, then the math is follows:
$900 x 1 ounce/31.10 grams = $28.94/gram
To find the value of jewelry:
You need to know the karats (weight) of actual gold in the jewelry.
24kt gold is the highest gold karat available and this is basically pure gold. 14kt and 18kt are common in the US, while 22kt gold is sold overseas. If you buy an 18kt piece of jewelry, this means that this jewelry is actually only 75% gold. The remaining 25% is other metals.
So if you have 1 gram of 18kt gold jewelry, you must multiply the price per gram x percentage of gold to find the actual price in grams. $28.94 x .75 = $21.71/gram.
Other factors will also affect the ultimate price, such as workmanship, gemstones, etc.
A gram of gold weighs approximately the same as a dollar bill and at today’s price is valued at $100.
These days, there are online calculators available that calculate the true current value of your gold.