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MOHS Scale

Hey, friends! Today I wanted to tell you a little bit about the MOHS scale of hardness, a tool in geology and gemology for measuring the hardness of minerals. Before I start, though, credit where credit is due: Meg helped me a bit with the details. =P She really is a good research assistant. (You should probably just assume she helps me with everything now, lol)

This scale ranks minerals based on their ability to scratch softer substances or be scratched by harder substances. The MOHS scale ranges from 1 to 10, with 1 being the softest (talc) and 10 the hardest (diamond). Each mineral on the scale can scratch those below it and be scratched by those above it.

When identifying minerals, a simple scratch test using common objects can help determine where a mineral falls on the MOHS scale. For instance, a fingernail (hardness 2.5) can scratch gypsum (hardness 2) but not calcite (hardness 3).

This scale has a few uses. One is that it can help you identify a crystal. Not sure if this is a piece of quartz or an especially clear bit of selenite? Try scratching it with your fingernail. If it doesn't scratch, it's harder than a 2.5 like selenite.

This scale can also help you figure out how to care for your crystals. If a crystal is on the softer side, you'll want to keep it away from salt. Anything lower than a 6 should be cleaned with nothing more harsh than a mild soap and water. If you want to make or purchase jewelry, knowing the hardness of certain stones can help you decide which one would be best to use for various purposes. For example, a soft crystal like selenite might be inconvenient in a ring, since the likelihood of being scratched would be higher than on something like a necklace. You should try to store your crystals with others of the same hardness so that you don't have to worry about them getting scratched.

Some minerals and their hardness levels

10 - Diamond

This scale can be very handy, as I'm sure you can imagine. If something has a hardness of 7, like quartz, it can be cleaned with soapy water and a soft brush. It's a fairly resistant little stone, but try to avoid dropping it on hard surfaces. Something with a hardness of 2, like selenite, should be cleaned with a soft, damp cloth rather than soaked in water, as soaking could cause scratches and slight dissolution. Store it in padding or wrap it in a soft cloth to avoid damage.

That's all I've got for you today. I hope this is helpful!

Stay safe!

- me (and Meg)

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