Gemstone Hardness and The Moh’s Scale
Diamond, which is the hardest naturally occurring substance, is highest on the scale, and talc, which can be scratched with a fingernail, is at the bottom. The position of a substance on the scale is determined by finding the hardest material that the given substance can scratch, and/or the softest material that can scratch the given substance. The scale is not even, as can be seen by the notes beside the minerals on the scale.
The Mohs' Scale
10 - Diamond (four times as hard as Corundum)
9 - Corundum (Ruby & Sapphire, twice as hard as Topaz)
8 - Topaz, Emerald, Aquamarine
7 - Quartz
6 - Orthoclase Feldspar
5 - Apatite
4 - Flourite (slightly harder than calcite)
3 - Calcite
2 - Gypsum
1 - Talc
Some examples of common substances that are rated on the Mohs' Scale are:
7-8 Steel
6.5 Glass
6 Titanium
3 Copper Penny
2.5-3 Gold and Silver
2.5 Fingernail
Common gemstones are rated on the scale as follows (from hardest to softest):
10 Diamond
9 Ruby, Sapphire
8.5 Alexandrite
7.5 - 8 Aquamarine, Emerald, Topaz
7 - 7.5 Garnet, Tourmaline
7 Onyx
6.5 - 7 Amethyst, Citrine, Tanzanite
6.5 Jadite, Peridot
6 Jade, Opal
3 Pearl
The hardness of minerals is important to jewelry artisans. They would not want to set a very hard stone next to a soft substance that can be scratched easily. Also softer stones are typically included in settings that are designed to protect the stone from wear. Generally valuable gemstones have a hardness of at least 7. Stones that are rated below 7 are likely to be damaged easily in jewelry that is worn everyday. The Moh's scale is a universal measurement scale that can be relied upon by jewelers to assist functional elements of jewelry design.
Category: Facts & Useful Info
About the Author (Author Profile)
Wanda Fitzgerald is a Florida native and an vintage charm collector who loves to share her adventures in an e-commerce jewelry business with anyone who is interested.Subscribe
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