Table of Contents
What is Gold?
What is the karat?
What is Gold Karat?
Gold Color
Hallmarking
Rhodium

18 KT GOLD & COLOR

Gold is a chemical element with the symbol Au and atomic number 79.

It is a dense, soft, malleable and ductile metal with a bright yellow color and luster, the properties of which remain without tarnishing when exposed to air or water.

What is the karat?

Since the pure gold is too soft to make exquisite jewelries. Therefore, the gold jewelries are almost alloy which are mixed with other metals, such as silver, copper, or zinc.

Pure gold is 24 karats. A unit karat of gold is equal to 1/24 part (4.1667%). The gold karat shows how many parts of gold and how many parts of other metals in a gold jewelry.

The following chart shows the differences between the different karats, and also shows the percentage of gold and other metals.

KaratsGold percentageOther Metal percentage
24Kgold 100.00%other metal 0.000%
22Kgold 91.60%other metal 8.4%
18ktgold 75.00%other metal 25%
14kt0.25 to 0.35mm0.35 to 0.5mm
10ktgold 41.7%other metal 58.300%
6ktgold 25%other metal 75%

18 Karat is 18/24 or ¾ of Pure Gold. "parts per thousand". Therefore, 18 Karat gold is, 750 parts per thousand. e.g.: ( 750 gms P.G. + 250 gms Alloys ) = 1000.00 grams 18 Kt Gold.

Gold Color :

  • 24 Kt. Pure Gold is Yellow Gold : We Can Change the Gold Colour after mixing Alloys.
  • 18 Kt White Gold = PURE GOLD + WD481CW (ALLOY)
  • 18 Kt. Yellow Gold = PURE GOLD + C183N (ALLOY)
  • Pure gold is available in 24k (0.999) & (0.995) fineness
  • However pure gold, by nature being soft is shortened into 18k, 14k & 10k.
  • Mixing alloys does the shortening process. This brings down the purity of gold.

Hallmarking :

The government has made hallmarking of gold compulsory, which is a purity certification of the precious metal. The Bureau of Indian Standard (BIS) under the consumer affairs ministry is the administrative authority for hallmarking.

All jewellery by law is required to be stamped so that the consumer knows the quality of gold used. Jewellery made in North America is typically marked with the karat grade Eg. 18K and jewellery made in Italy is typically marked with the fineness such as eg. 750. So if your jewellery does not have a karat grade stamped on it, check for a 3-digit fineness number.

When trying to decide between the gold karat types there are three things to consider:

  1. The metal's performance with every day wear.
  2. The difference in color between the 10kt, 14kt and 18kt gold.
  3. The difference in price between the gold karats.

The BIS Hallmark & the 750 mark can be seen in the Image.

RHODIUM :

Rhodium is a plating process.Rhodiumis a very hard and durable metal related to platinum metals. Over a period of time white gold often show a yellowish cast of color due to the natural tarnish Rhodium is often plated over white gold to help keep the white gold looking white.

It is a plating process normally undertaken to give a bright silvery white look to the jewellery. We also rhodium plate any yellow gold piece to give it a temporary white gold look & effect. The rhodium plating normally wears off with usage & time.

NOTE : The plating of rhodium can wear off depending upon the customers use.