Mohs’ hardness is a measure of the relative hardness and resistance to scratching between minerals. Other hardness scales rely on the ability to create an indentation into the tested mineral (such as the Rockwell, Vickers, and Brinell hardness – these are used mainly to determine hardness in metals and metal alloys).

mineral hardness

The Mohs’ scale is not very useful for identifying minerals. 5. All rocks are made of minerals. 6.

Mohs Hardness Scale Quartz is a 7. It can be scratched by topaz, corundum, and diamond.

However, alone, tungsten has the highest melting point and also the highest tensile strength of any pure metal on the periodic table, making it a top contender for the strongest metal on the planet.

Tungsten

rhodium

The higher the score, the harder the metal. Vickers hardness of 9ct gold is between 80 to 120 (depending on the other constituents of the alloy and the condition of the material). 18ct gold receives a score of between 135 to 165. So 18ct gold is harder than 9ct gold – science fact!

24 karat

Apart from jewellery, CaratLane offers 22k (916) and 24k (995) gold coins with certification and the guarantee of a BIS Hallmarked stamp.

14K

KDM gold on the other hand provides no guarantee on the purity and fineness of gold jewellery as it’s not certified. It’s quite simple to say that hallmarked BIS 916 gold would be the better choice when the purity is of greatest concern.

KDM means gold mixed with cadmium. This could be mixed in the ratio of 92% and 8%. Cadmium-soldered jewelry is widely known as KDM jewelry. Cadmium has been replaced with Zinc and other metals. The term ‘KDM’ still sticks and KDM jewelry has the same purity even when melted.

Usually, jewelers cheat customers by selling low carat gold at a high rate. That means jewelers sell 18 carat gold and charge the price of 22 carat gold.

BIS hallmark

916 gold