If you've shopped with us at Sailor, you may have noticed that our ring selection heavily favors diamonds and sapphires, though our earring, necklace, and bracelet selection varies across a spectrum of gemstones. Moreover, if you came to us for an engagement ring, you may have even been talked out of an opal or a pearl ring. Why is that? The answer is explained by the frequency of wear in context of the gemstone's relative hardness, or Mohs Hardness.
Mohs Hardness
In 1812, the mineralogist Friedrich Mohs (1773-1839) established a reference scale of ten common minerals, ranked in order of increasing hardness. This scale, shown below, is called the Mohs scale of hardness and is still widely used today, with additions.
| 10 | Diamond (hardest of all, four times as hard as corundum) |
| 9 | Corundum: Sapphires and Rubies (twice as hard as topaz) |
| 8 | Topaz, Aquamarine |
| 7 | Quartz, Emerald (has the ability to scratch glass) |
| 6 | Feldspar, Moonstone, Labradorite, Opal (can be scratched by a steel file) |
| 5 | Apatite |
| 4 | Fluorite (can be scratched by a common knife) |
| 3 | Calcite, Pearl (can be scratched by a coin) |
| 2 | Gypsum, Amber |
| 1 | Talc (can be scratched by a fingernail) |
Now, back to our ring selection: Think of how many times every day you put your hands inside pockets, purses, glove compartments, and desk drawers. Now think of what brushes against a ring when you do those things. Lastly, think of which pieces of jewelry you wear most frequently, perhaps even continuously. If you thought of your wedding set or a family heirloom ring, you're not alone!
Gemstone hardness contributes greatly to the degree to which a gem will show wear. This is often referred to as wearability or sometimes “durability.” An opal with a hardness of 6 will be rapidly covered with fine scratches and lose its polish if worn everyday as a ring stone. Quartz (hardness 7) is a component of dust and one of the most common minerals on Earth. Simply wiping off dust from a softer material will scratch it. The scratches may be tiny, even microscopic, but they’ll accumulate and become visible over time. On the other hand, a ruby with a hardness of 9 will remain bright and lustrous for years because it’s harder than most of the abrasive particles that contribute to wear.
Sailor is owned, curated, and staffed by fine jeweler Sarah McGuire with help from fine jeweler Maura Dolphin of auram. When you shop with us, you can trust that we pride ourselves in guaranteeing that the gemstone you select suits the durability of a lifetime of wear.
Source: International Gem Society