Gemstone Mohs hardness pencil

For testing the hardness scale of minerals Other hardness scale available

Hardness pencils are pencils with a tip made of one of the 10 minerals on Mohs scale.These pencils are used to try and scratch a stone and observe if the pencils can scratch the gem. Since this is a destructive method (it leaves a scratch), this test is mostly used on pieces of rough or on a inconspicuous place on the gemstone. Not many gemologists use this test as there are better ways to determine a gemstone's identity.

When one does feel the need to apply this test, one must do it in a logical manner.The gemstone is tested with a pencil of low hardness (starting at 4 or lower) to try to put a tiny scratch on the stone without applying pressure. If no scratch is observed, one repeats this process with a pencil of higher hardness (in this case 5) and so on until one arrives at the pencil that is able to put a tiny scratch on the stone.For instance, if one could not scratch the mineral with pencil no.7 but it would leave a scratch with pencil no.8, the hardness of the mineral must be between 7 and 8 on Mohs scale.

Mohs Hardness:5-9Gift box packageThe Hardness Pencil:qpatite-5; orthoclase-6; quarta-7; topaz-8; corundum-9 ,Those minerals are mounted in five metal pole respectively,use the corner of those mineral to scratch the gem,you will get the hardness according to the nick you scratch,If there is a nick after you scratched, the sample's hardness is lower than the standard hardness pencil; If there is no nick after you scratched, that means the sample's hardness is higher than the standard hardness pencil.

Gemstone Mohs hardness pencil