When you select a treasured piece of jewellery, its sparkle and colour are often what first captivate you. Yet beneath the surface of every gem lies a vital characteristic that dictates how you should care for it: its physical resilience.
This is often measured using a comparative reference known as the Mohs scale, which assesses a material's resistance to surface scratching. The Mohs scale ranks minerals from 1 (the softest) to 10 (the most resistant to abrasion).
This ranking is relative. For example, despite a diamond being ranked a 10 and a ruby being ranked a 9, a diamond is still over 100x harder than a ruby.
Understanding where your gemstone falls on this scale determines its suitability for daily wear and guides proper cleaning methods.
Hardness vs Durability
It's crucial to recognise that a stone's resistance to scratching, "hardness", is distinct from its resistance to breaking or chipping "durability". When choosing a gem, remember that resistance to scratching is only one component of how tough your gemstone is. Durability plays an equally important role.
Cleavage refers to a mineral's tendency to split cleanly along internal crystal planes when struck, whilst toughness refers to its overall resilience against breaking or chipping.
Jade, for example, is renowned for having perhaps the greatest toughness of all gem materials, despite its moderate scratch resistance (Mohs 6 to 7). It's like tightly knit chainmail, offering impressive resistance to breaking even if the surface can be scratched.
Conversely, gemstones such as topaz (Mohs 8), whilst harder than many other materials, contain cleavage planes that make them vulnerable to a sharp blow in the wrong direction.
The Delicate Divide
As we move down the Mohs scale, gemstones become increasingly sensitive to everyday wear. Stones ranked below 7 are vulnerable to common household dust, which often contains quartz particles (Mohs 7). This is why softer gems must be stored separately in protective packaging and cleaned only with soft cloths.
Stones that rank even lower, such as fluorite (4) and malachite (3.5 to 4), are particularly fragile. They need secure settings or are best reserved for pieces less prone to impact, like earrings or pendants.
To maintain the beauty of your precious possessions, always confirm the Mohs ranking and specific durability notes of your stones. Pay particular attention to whether they've received any stabilising treatments that might affect their reaction to heat or chemicals.
Understanding these characteristics ensures you can enjoy your jewellery for years to come whilst preserving its beauty and integrity.
Gemstone Hardness and Care Guide
We've put together an easy to reference guide below for your gemstone. For gemstones set in jewellery, we recommend also referring to our The Essential Guide to Caring for Your Jewellery by Metal . It is recommended to use whichever cleaning or storing method is gentler for your particular combination of gemstone and metal.
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