Choosing a stone: hardness, durability, and long term wear
Not all stones are created equally and while shopping for jewelry knowing the durability of a gemstone will help you decide not only how and when to wear the piece, but how to care for it as well. Some of you may have heard of the Mohs scale, it ranks gem and mineral hardness on a scale of 1 (least hard) to 10 (hardest of all). However hardness is only one factor when determining a stones durability. Durability is defined as a gemstone's ability to withstand daily wear, various chemicals, light and humidity. As gemstones hold different properties their tolerances to these stressors differ. There are 3 factors to consider (hardness, toughness, stability) when evaluating a stone’s durability and no single gemstone is perfect so you should weigh all these factors when choosing a stone for a piece of jewelry that is going to be right for your type of lifestyle.
Hardness
A gemstone’s hardness is a good indicator of how well it will withstand scratches. However the Mohs scale isn’t linear, instead gemstones are ranked on a relative scale based on their scratch hardness. For example while a corundum (rubies, sapphires) are a 9, a diamond at a hardness of 10 is many times harder. Only a diamond can scratch a diamond where a corundum can scratch itself and anything softer, topaz (8) quartz (7) etc. Because of these properties how you store your jewelry is crucial to avoid scratching. Keeping gemstones from touching will prolong the life and ultimate wear of your precious pieces.
Toughness
The molecular make up of gemstones determine their toughness, aka how it resists breaking and chipping. A toughness sale measures the work needed to separate the surfaces of a crystal along a plane. Values for diamond range from 5,000-8,000 where corundum is around 600, obviously not as tough. However even though diamonds are considered fairly tough, a hard hit can fracture the gemstone in certain directions. Certain cuts with exposed points like marquises and pears are more at risk for chipping. Choosing the appropriate type of jewelry and setting will help protect your gemstone from an accidental fracture. For example opals or moonstones which aren’t so tough hold up more to daily wear in earrings or a necklace. I love opal rings and make several of them, but depending on your lifestyle you may end up replacing the gemstone more often than you may like if you plan to never take it off. Also choosing settings that properly protect stones with exposed points (pears, marquises) will prevent chipping. For example two good choices for those type of stones would be v-shaped prongs in a basket setting or a lower profile setting with an edge where the point has more protection like the aria ring from my collection. It’s also wise to check your jewelry often, settings can get loose over time it’s not always a manufacturing issue but rather from daily wear and tear. Noticing when gemstones get loose will ensure you can get them tightened up before causing damage to the stone in your beautiful piece of jewelry. Most local jewelers can help you with this and if you purchased the piece from me I can as well!
Stability
How well a gemstone can deal with exposure to chemicals, light, humidity or temperature changes will determine the stability. Some of the key causes of damage to a stone are extreme changes in temperature, humidity levels, prolonged exposure to sunlight and exposure to harsh chemicals. Diamonds and Moissanites are extremely stable but sudden changes in temperature can under certain circumstances create fractures or cause existing ones to worsen. Stones like opal and tanzanite however are more at risk for fracturing due to changes in temperature. Other gemstones are more susceptible to the surrounding humidity. Opals are known to lose moisture in low humidity which can cause them to crack. Storing them in a cool jewelry box will help prolong their lifespan. On the other hand too much moisture is also bad, stones like amber and malachite can be damaged by water so definitely leave those in the jewelry box if you plan on going for a swim. Stones like citrine, amethyst and topaz can actually change color or fade from long term exposure to heat or light. Glass enamel also may be ruined by contact with heat, so it is best to store those pieces out of sunlight when not wearing. There are a lot of chemicals that can damage delicate organic gems like pearls, opals and turquoise. Chlorine, perfume and even some makeups will put your precious pieces at risk. My favorite rule to follow when wearing jewelry is it should be the last thing you put on and the first thing you take off.
Gemstones have been sought after for their beauty and sparkle for thousands of years and when properly cared for, they become the treasured pieces in your family that can be passed down through generations. Are you ready to create a gorgeous one of a kind gemstone beauty now that you know about hardness, toughness and stability? Check out the custom page here to get started!