What gemstones are suitable to wear everyday?
Lots of people come to me with ideas for an item of jewellery they have, and inevitably I end up telling them that what they want is by all means possible but not practical. In order to understand why we have to go into a little bit of science... Different gemstones have different hardnesses (MOHs scale), but they also have various degrees of toughness. What's the difference? I hear you ask. Well let's start with the definitions. Hardness is the ability of one material to scratch (or resist scratching) from another, each number in MOHs scale is defined by one particular gemstone type, where 1 is the softest (defined by Talc) and 10 is the hardest (defined by Diamond). The problem with this scale is it is not a linear scale, for instance the gap between 9-10 is greater than the jump between 1-9, so you can see that Diamond as a material is much, much harder than any other gemstone.
Now on to toughness, which is the ability of a material to resist fracture. Toughness is mainly down to the particular crystal structure of the material. Diamond belongs to the cubic crystal family, and is a very tough material but does have what is known as 'perfect cleavage'. This means that with a hard enough blow on one of the planes running through the stone, it is possible to break it. This is indeed how stones used to be cut before technology advanced. Certain gemstones such as Sapphire & Ruby (both Corundum) are both hard (9 on MOHs scale) and have a tough crystal structure, this makes them suitable for everyday wear. Other stones such as Onyx (commonly seen in signet rings and deco jewellery) have an incredibly complex crystal structure but are not that hard.
So we can see that we need to consider both factors when determining the potential durability of a stone. Diamond is the obvious choice for anyone wanting a gemstone that will continue to look good for generations, we often see antique jewellery that is worn but the diamond looks as good as the day it was cut.
With stones like Sapphire & Ruby, we commonly observe that the facets can be abraded and sometimes the stones can be chipped. With larger more valuable stones, these abraded facets can usually be re-polished to bring them back to their former glory with minimal carat weight loss.
If you're looking for a colourless gemstone we would always recommend diamond as the number one choice to customers, it is expensive but not only wears well, Diamonds also have a unique property known as 'Total Internal Reflection'. This is why the stones are so bright and sparkly, the light that enters the stone is bounced around the inside and reflected to the wearer. We see flashes of colour in the stone as the white light entering is broken down into its spectral my counterparts (a bit like a prism effect).
If you're after a coloured stone of some kind, we would recommend Sapphire (Ruby is the term we reserve for purely red varieties of Corundum). Sapphire comes in many colours; Blue, Green, Purple, Orange, Yellow, Pink and even Colourless. The best (and usually most expensive) stones have minimal inclusions visible by eye or under 10x loupe, and normally have a vivid colour or strong saturation.
Suitable to wear everyday:
Sapphire & Ruby (all colours)
It is worth noting that other popular gemstone varieties like Topaz, Aquamarine, Quartz (including Amethyst & Citrine), Garnet, Turquoise, Periodot all have hardnesses between 6.5-7.5. This means that these stones, when worn everyday, can show surface abrasion. Emerald as a gemstone is very Brittle (the opposite of the tough gemstones), this means they are prone to breakage and as such should be carefully considered as a choice of gemstone in rings, even a small knock to this gemstone type could break it.
Wear with care:
Quartz (citrine & amethyst)
Other materials like Coral, Amber, Opal, Ivory and Pearl which are not Gemstones but 'Organic Materials' are much softer than most actual gemstones and therefore extra care should be taken with these. They are most definitely not something you should be wearing everyday.
Having said this, softer gemstones as mentioned above are very well suited to Necklaces, Pendants and Earrings. The reasoning behind this is that they are less likely to come into contact with anything when worn in this way. Gemstones in rings suffer the most from day to day knocks and blows.
Abraded facets can be seen on the underside of this Glass Doublet Gemstone