Wednesday, December 15, 2010

How to Evaluate the Purity of Gold: Gold Carat and Purity

Tips for Identifying Gold Hallmarks

It is said that more than 40% of the gold products in the world is bought by Indians! Gold is considered as a commodity, and not a product. We Indians culturally have fascination for wearing these beautifully crafted gold ornaments and jewels in every visible part of their body since from our ancient times.

For Hindus, jewelry is associated with most religious ceremonies, especially the samaskaras (stages of life) such as the namkarna (naming ceremony) or the vivaha (marriage). To signify marital status, Hindu women must wear the mangalsutra or the thali, which consist of gold pendants strung in a certain combination with other beads. Traditionally, a goldsmith pierces a child's ear with a gold pin twelve days after it is born. The variety of our ornaments bears the testimony to the excellent skills of the jewelers in India.

You may conclude that demand for gold India is not price-elastic. But it is prosperity elastic - that is, jewelry serves as an identity marker and the prosperity is generally matched with the purchases of more gold.

Use this gold information to learn more about this precious metal. Here's how to evaluate the purity of gold.

Properties of Gold

You may wonder to know that this soft metal is very malleable and corrosion-resistant and generally does not cause reactions on skin for the vast majority of people. From any chemistry text book you may understand that gold has melting point at 1064 deg. C and boiling point at 2808 deg. C.

As gold is very soft, jewelers mix copper, silver, palladium and nickel to harden it. The gold you see in your gold jewelery is actually gold alloy. The alloy, suitable for jewelery-making, will influence the final colour of the gold -- nickel would produce a whiter tone than copper, which will produce a yellow metal.

Carat and Purity

Now we try to understand few interesting facts about the metal that we all cherish so dearly. The purity of gold is measured in Carats. The term Carat was used hundreds of years ago in the Middle East. Caratage is an important factor in buying gold jewelry as it indicates how pure the metal is.

The gold Carat (ct) tells you how many parts of gold and how many parts of other metal are in the gold alloy. Jewelry standards specifies the benchmarks for gold to ascertain its fineness i.e., parts per thousand. For example your 24 Carat gold is considered to be 999.999 parts per thousand. One carat is one part of 24, or 41.66 parts of a thousand.

Now you may understand the basis that there can never be a total and absolute purity of gold. Your 22 Carat gold is 22/24th (gold is 916.000 parts per thousand and other metals have 84 parts). Your 18 Carat gold is 18/24th (gold is 750 parts per thousand and other metals have 250 parts). Similarly your 14 Carat gold is 14/24th or 585.000 parts per thousand and other metals have 415 parts. Your 9 Carat has this ratio: 9/24th (gold is 375.000 parts per thousand and other metals have 625 parts). This system of calculation gives only the weight of pure gold contained in an all.

Acid Test Kits and Electronic Testing Kits

You can test the purity of gold yourself with the right test equipment. The acid solutions are marked with various Carat gold strengths, usually 22K, 18K and 14K. A touch stone is a ground black glass sheet or similar. What you need to do is go through the surface of the gold by using a file or blade in an INCONSPICUOUS place.

File or cut into it a small amount and then place a drop of, say 9K acid, directly on the cut. If no reaction then it is at least 9K. Use the next highest acid (say 14K). If no reactions, then try 18K acid. No reaction? Then you know it's a least 18K gold. If some reaction, say the cut turns brown, the gold is lesser than your acid strength. Proceed to apply lesser strength acids till there is no reaction.

Bear in mind however that any testing of gold with chemicals will mean a loss of some small amount of gold. Electronic gold testing is now becoming popular and electronic testers can be found with a little investigation and research, and money. Testing gold is a great way to determine fool's gold from pure gold.

Hallmarking of Gold

Now let me discuss about hallmarking of gold. What is hallmark? Hallmark is a purity certification of gold articles in accordance with Indian Standard specifications. India Bureau of Indian Standard (BIS) was named as the sole agency in the country for Hallmarking of gold jewelry under the provisions of the BIS Act, 1986. BIS is primarily engaged in the preparation and promotion of standards and operation of different quality certification schemes. You might have noticed hallmark seal placed on gold ornaments and jewels in jewelry houses. If not noted, at least from now onwards you ensure this mark on your jewelry. This is why identifying gold hallmarks is important. Your hallmark comprises five elements

* BIS Mark
* The fineness number (corresponding to given caratage)
* Assaying and Hallmarking Center's mark
* Jeweler's mark
* Year of marking denoted by a code letter and decided by BIS (e.g. code letter 'A' was approved by BIS for year 2000, 'B' being used for the year 2001 and 'C' for 2002).

The marking is done either using punches or laser marking machine. Its purpose is to safeguard the consumers. The meaning of this mark is that the assayers (an independent body - assay office) guarantee the legal standard of fineness or purity. This mark applies for both buying and selling of ornaments and jewels.

Hallmarking is the reliable certicification scheme. But its implementation is not complete in all respects. It seems only more fashion jewelries are sometimes less reliably hallmarked. So be cautious. While buying gold check it yourself if you feel confident or have it checked by a professional. LASTLY, I would like to point out that I am not a jeweler and that the above guidelines are not provided out of expertise in gold ornaments.

Required Tools:

* Self knowledge about caratage, touch, halmark or Professional Expertise and Guidances
* Understanding about BIS i.e. promotion of BIS standards and its and operation of different quality certification schemes.
* Understanding of Acid Test Kits and Electronic Testing Kits

Quick Tips:

* Caratage is an important factor in buying gold jewellery as it indicates how pure the metal is. One carat is one part of 24, or 41.66 parts of a thousand.
* You can test the purity of gold yourself with the right test equipment - i.e. acid test kit or electronic test kit
* In India Bureau of Indian Standard (BIS) was named as the sole agency in the country for Hallmarking (purity certification) of gold jewellery under the provisions of the BIS Act, 1986.

Useful Links:

* Bureau of Indian Standards BIS Criteria for Recognition of Assaying and Hallmarking Centers
* Fake gold or real? A few hints and tests.

1 comment: