Gemselect Gemstone Rings - What you should know about Durability and Hardness
The durability and hardness of a gemstone is an extremely important factor to consider when designing jewelry, especially for gemstone rings. Reason being, is that most rings, such as engagement rings or wedding bands, are worn on an almost daily basis. Every day, your gemstone ring may be left vulnerable to situations that can easily damage your precious gemstone. The damages can range from small surface scratches to small chips to complete fractures, or even a lost stone. All of the aforementioned situations would be so sadly detrimental, especially for anything with substantial sentimental value.
So, this age-old question is - which gemstones are considered durable enough to be used and worn in everyday jewelry? Also, which gems would be acceptable on a more occasional basis for ring-wearing?
One important factor in determining the durability of a gemstone is its hardness. Gemologists use an official grading scale of hardness and they measure and grade gemstone hardness accordingly. This official gemstone hardness scale is known as the Mohs scale of hardness. The Moh's scale of hardness essentially assigns minerals with a numerical value between 1 and 10, with 1 being the softest and 10 being the hardest. This official grading scale has been in use since 1822 and was created by German mineralogist, Frederick Mohs. The hardness scale defines the numerical value assigned to each mineral based on in its scratch resistance. In simple manner, a mineral with a higher numerical value can scratch a softer one with a lower value, but not the other way around.
On the Mohs scale, diamond is graded the hardest (10), meaning that it is capable of scratching any and all other minerals: ruby and sapphire is 2nd to diamond at a 9; topaz, spinel and emerald are at an 8, and Garnet, quartz and tourmaline are graded 7. Orthcoclase - 6, apatite - 5 and softer gems include: fluorite - 4, calcite - 3, gypsum - 2 and talc being the softest at 1. To get a better understanding of this scale, you can see that Topaz is an 8, so it is capable of scratching all the gems with a lower rating (garnet, apatite and etc), but it cannot scratch diamond or corundum (sapphire and ruby).
There has always been a rule of thumb generally accepted, where basically any gemstone with a hardness level of 7 or more is considered durable enough for everyday ring-wearing. This is because the line between hard and soft gems is believed to be at Mohs rating of 7, where gems with a hardness of 7 or more are suitable for rings, while those below 7 are not. The reasoning for this is that ordinary dust can consists of quartz and so just by simply wiping your gemstone clean with a cloth, the quartz dust could potentially scratch your softer gemstone. However, even with this rule of them, there are many exceptions and variables to consider.
For any jewelry designs, such as wedding bands or engagement rings that are intended for everyday wear (especially over a period of years), it is suggested to source a gemstone with a hardness rating between 8 - 10. As noted above, there are always exceptions to be had. For example, even though emerald has a hardness of 8, because of its natural heavy inclusions, it is not considered an ideal gem for every day wear.
For precious colored gems that fall into the 7 or greater group, such as quartz, garnet, zircon, tourmaline and beryl -- these are considered to be very suitable in occasional wear ring designs. Should you decide to use one of these gem types in an everyday wearing design, than it is suggested to use a protective style of gem setting, such as a bezel or channel setting style.
For those colored gems with hardness below 7, they are not necessarily excluded from being used in ring designs as long as caution and care is taken while wearing the jewelry. Wearing of the softer gemstone type rings should be limited to 'special occasions', and extra awareness and preventive maintenance should be taken. Despite being considered soft, tanzanite and opal are frequently used in ring designs. The owners of these rings are just extra careful in the way they wear them.
There are also quite a few gemstone types with a hardness level less than 7 that are still considered extremely durable (meaning that hardness is not the only consideration). Take nephrite and jadeite for example; these are two different varieties of jade and although nephrite is graded 6 to 6.5 and jadeite 6.5 to 7, both are these are considered very durable and tough because of their internal structures which naturally tend to resist fracturing. However since these are both softer gems, repolishing is typically needed every so often to remove small surface scratches and to retain that wonderful jade vitreous, silky luster.