Gem Stone Hardness
The hardness of a gem stone is measured by its ability to resist scratching. The jewelry trade relies on a unit
of measure called the Moh's hardness scale to define the fragile nature of one stone compared to another.
The system was developed by German gem expert, Friedrich Mohs in 1812 and is still in use today. The scale involves
a numerical value of 1 through 10, with 1 being the most easily scratched, and 10 being the most scratch-resistant.
Mohs developed this scale by rating 10 common minerals: talc, gypsum, calcite, fluorite, apatite, orthoclase,
quartz, topaz, corundum and diamond.
He discovered that each of these minerals can scratch those assigned a smaller number, and in turn can be scratched
by those with a larger number. All gem stones are rated according to this scale by comparing their hardness with
these originally selected 10 minerals.
The hardness of a gem stone is useful to know when considering which stones will be best for daily wear and
which are best for occasional wear. Obviously a bracelet will get more wear and tear than a pair of earrings.
Knowing the hardness of your gem stones can also assist in choosing appropriate cleaning methods and overall
care of the stone.
Gem Stone Toughness
While hardness lets us know the scratch resistance of a particular stone, toughness indicates its resistance
to breaking. This is an important factor to consider when choosing a durable stone. The hardness and the toughness
of a stone can vary considerably.
For example, though a diamond has a hardness rating of 10, its toughness rating is only 'good'. Jade, on the
other hand, is easily scratched but is highly valued as a carving stone - being rated as 'extreme' in its toughness.
When purchasing a stone, you should consider its durability in relation to its intended use. Any gem, if cared
for properly, will provide years of enjoyment for its wearer.
Find your gemstone on the Moh's Scale.
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