Written by Bérengère Treussard - Wednesday, March 13, 2024
The Mohs scale is a tool for measuring the hardness of minerals, created by the German mineralogist Friedrich Mohs in 1812 and now used worldwide. This scale is employed in the jewellery industry to assess the resistance of gemstones.
The hardness of a stone is a crucial factor to consider in jewellery making, as it determines their durability and ability to withstand daily wear.
Not all types of stones are suitable for jewellery. In fact, some stones are never used in jewellery, even though they are beautiful stones. Understanding this scale also helps ensure
According to French regulation, all stones, whether precious or semi-precious, are designated as "precious stones". The term "semi-precious" cannot be used in French, unlike in English-speaking countries.
In this article, we will delve into the Mohs scale in detail and examine the use of certain gemstones in jewellery making.
The Mohs scale is a measurement scale of mineral hardness, which ranks minerals from 1 to 10 based on their resistance to scratches. The softest mineral, talc, is ranked at 1, while the hardest mineral,
Diamond is the hardest gemstone on the Mohs scale. Due to its exceptional hardness, it is used to create durable and scratch-resistant jewellery, such as
Sapphire is a gemstone prized for its deep blue colour. With a hardness of 9 on the Mohs scale, it is used to create durable and resistant jewellery pieces, such as rings and bracelets. Sapphire is also available in other colours, such as pink and yellow (but not red, which is a ruby), making it a versatile choice for bespoke jewellery. One can create stunning rainbow-colored jewellery entirely with sapphires.
Ruby is a highly prized gemstone due to its intense red colour. Ruby has the same hardness as sapphire because it comes from the same material, corundum, an aluminium oxide that is coloured by chromium when it's red. With a hardness of 9 on the Mohs scale, it is considered one of the hardest stones after diamond. Ruby is used to create fine jewellery pieces such as rings and necklaces. Its vibrant colour and durability make it a highly appreciated gemstone in the world of jewellery.
Topaz comes in a variety of colours, including blue, pink, and yellow. With a hardness of 8 on the Mohs scale, topaz is used to create durable and resistant jewellery pieces for daily wear. Topaz earrings add a touch of sophistication and charm to any outfit.
Emerald is a precious stone prized for its intense green colour. Although it is not as hard as diamond or sapphire, it is used in the manufacture of high-quality jewellery. Emerald is often associated with rings and necklaces and is prized for its unique beauty and symbolic meaning of love and fertility.
Tourmaline has a wide spectrum of colours as it can have up to 7 shades. It's an extraordinary stone that can take on different colours depending on its chemical composition, ranging from black to green, blue, turquoise blue, pink, or bicolour or multicolour depending on how it is cut. The most prized colour is turquoise blue, known as Paraiba tourmaline, which you will often see in fine jewellery sets.
Garnet comes in a variety of colours, ranging from deep red to green and purple. With a hardness of 6.5-7.5 on the Mohs scale, garnet is used to create jewellery such as rings, necklaces, and earrings. Garnet is appreciated for its brilliance and versatility in terms of jewellery design. My favourite garnet is rhodolite garnet, which has a rosy wine colour that I adore.
Tanzanite is a relatively new gemstone in the jewellery market. With its unique blue-purple colour, it is becoming increasingly popular in the creation of modern jewellery. Although its hardness is relatively moderate on the Mohs scale, tanzanite is used in the manufacturing of rings, pendants, and earrings. Its rarity and beauty make it a coveted gemstone.
Opal is appreciated for its unique beauty and colourful flashes. Although it is not as hard as some other gemstones, opal is used in the creation of artistic and unique jewellery. Opal rings and earrings add a touch of mystery and magic to your jewellery collection. Legend has it that opal brings bad luck: in the Middle Ages, clumsy jewellers who broke opals, due to their low hardness, lost their hand because of this clumsiness.
Pearls are organic gems formed inside mollusc shells. They are often used in the making of elegant and classic jewellery such as necklaces and earrings. Although pearls have a relatively low hardness on the Mohs scale, they are highly valued for their natural beauty and unique lustre.
The Mohs scale is an essential tool in the jewellery industry as it helps assess gemstone hardness. By understanding the hardness of stones, jewellers can create durable and wear-resistant jewellery.
Whether it's diamond, sapphire, emerald, or other stones, each gem has its own place in the world of jewellery due to its unique beauty and symbolic significance. When choosing a piece of jewellery, consider not only the brilliance and colour of the stone but also its hardness to ensure that your jewellery remains beautiful and intact over the years.
However, nothing lasts forever – a stone may become scratched and may require re-cutting to give it a new life. Lapidaries are specialists in stone cutting and can restore a stone's shine. Of course, certain rules should also be respected when wearing jewellery with stones, such as avoiding sports or manual labour that could damage them.
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