This scale was devised by a german mineralogist frederick mohs in 1822. A 7 or higher on the mohs scale usually indicates a gem is hard enough for normal jewelry use. Fro example corundum sapphire and ruby was used to scratch apatite corundum left a scratch on the surface of apatite and so this mineral should sit higher on the scale. The mohs hardness scale starts with talc at 1 being the softest mineral and ending with diamond at 10 being the hardest mineral. Wearability can be graded as excellent very good good poor or display only.
It defines hardness in terms of scratch resistance where a harder mineral will scratch a softer one but not vice versa. Only a diamond can scratch a diamond. Mohs hardness scale for gemstones. In gemology gem hardness is measured on a scale known as the mohs scale which assigns minerals a value between 1 softest and 10 hardest. Corundum can scratch itself topaz 8 quartz 7 and anything softer.
The method of comparing hardness by observing which minerals can scratch others is of great antiquity having been mentioned by theophrastus. The most expensive gemstone based on the price per carat rubies stand at a mohs hardness level of 9 which makes them quite strong and scratch resistant. The mohs scale is a not a linear scale. A scratch test is not really recommended as using something harder than 7 5 on the mohs scale to scratch a sample would only end up possibly damaging a valuable gemstone and using a potential grandidierite to mark glass or a weaker material is risky too. Find the traditional scale here and a chart of select gems ordered by hardness.
RELATED ARTICLE :
Instead it ranks gems on a relative scale based on their scratch hardness so although corundum ruby or sapphire is a 9 a diamond at 10 is many times harder. The mohs scale was created by trying to scratch one mineral with another and then recording which mineral left a scratch. The mohs scale of mineral hardness is a qualitative ordinal scale characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. It is universally used around the world as a way of distinguishing minerals. The higher the number the harder the mineral.The mohs hardness scale measures a mineral s resistance to scratching. Pearls and opals are some of the most popular jewelry gems but are well below 7. This is a guideline not a hard and fast rule. The mohs hardness scale measures a mineral s resistance to scratching. Instead it ranks gems on a relative scale based on their scratch hardness so although corundum ruby or sapphire is a 9 a diamond at 10 is many times harder.
This is a guideline not a hard and fast rule. The method of comparing hardness by observing which minerals can scratch others is of great antiquity having been mentioned by theophrastus. It defines hardness in terms of scratch resistance where a harder mineral will scratch a softer one but not vice versa. This scale was devised by a german mineralogist frederick mohs in 1822.
