How to Use the Mohs Scale for Gemstone Jewelry Care

In order to properly clean and care for your jewelry, it’s essential to understand the components that make up the piece. The hardness of the gemstone dictates what type of cleaning formulation is safe to be used. Most consumers have a vague idea that some gems are harder than others. It’s pretty common knowledge that diamonds are hard and that pearls are softer. But how can you determine how hard other stones are?

If you ask your jeweler that question, she will likely reference the Mohs scale. The Mohs scale of mineral hardness characterizes how scratch resistant various minerals are. Minerals are compared by their ability to scratch the surface of other minerals. The scale is named for German geologist and mineralogist Friedrich Mohs, who created it in 1812.

Ten minerals make up the scale, and all other minerals fall on the scale based on the hardest mineral that mineral can scratch. The Mohs scale minerals range from softest (talc) to hardest (you guessed it – diamonds). The scale does not measure absolute hardness, but rather the relative hardness of one mineral to another.

What does that mean for cleaning your jewelry?

You need to be cautious of the type of jewelry cleaning formulation you use for different types of jewelry.

• Most fine jewelry cleaning formulations, with or without ammonia, are safe for gems on the harder end of the scale, such as diamonds, amethyst, rubies, sapphires and topaz. We recommend our Fine Jewelry Cleaner for gems that are ranked harder.
• Jewelry cleaners marketed as “gentle” or “delicate” may be safe for use on softer, more porous gemstones. You should read the directions on the jar or check with your jeweler to be sure. Gem Glow’s Delicate Jewelry Cleaner has been fully tested and is safe for all jewelry, including pearls, treated diamonds, treated rubies, doublets, emeralds, opals, beads and fashion jewelry.
• Despite being made of all-natural ingredients, natural jewelry cleaning formulations may still be too harsh for softer gemstones. Again, you should read the jar or talk to your jeweler for guidance.
• Silver jewelry cleaners are formulated to remove tarnish from sterling silver jewelry and should not be used on gemstones or even silver with designer antiquing. Always be sure to thoroughly read and follow the instructions on the jar of Gem Glow Silver Cleaner.