![]() ![]() ![]() Gemstones have either none or 1 to 5 planes of cleavage. Cleavage is the crystal tendency to break along a particular plane. To make things even more confusing, gemstones have another property called ‘cleavage’. While not as brittle as many other gemstones, diamonds can still be chipped or shattered, care must be taken to not expose them to high impacts or leverage. As mentioned previously, hardness doesn’t necessarily mean toughness. People are often surprised to learn that diamonds can be broken. This is great for jeweller, as the brightness and sparkle of a diamond will usually last a lifetime. They are one of the hardest know materials, and will endure amounts of surface wear and tear. Many believe diamonds to be indestructible. Stones such as Columbian Emerald and Topaz are hard but extremely brittle, making them best suited for earrings, pendants and other low wear pieces. There are definite gemstone parallels with this line of thought. Hardness and toughness are often directly related, in that a material that rates well with one is generally poorer with the other. Perspex is a tougher material in that it can be bent as well as absorb an impact, yet it is not very hard, as it can be easily scratched. Glass wont scratch easily, but is not flexible and is prone to shattering. An analogy previously mentioned in 18ct gold vs. Toughness is a measure of the ability of a material to absorb energy, and is a measure of how likely a material is to snap, chip or shatter. Hardness depicts a materials ability to stand up to wear or abrasion, typically the harder a material is the more stiff or brittle it becomes. Mohs scale relates to ‘hardness’ and not ‘toughness’. At Metal Urges we only sell handmade jewellery containing hard stones such as diamond, sapphire, ruby and alexandrite. For your jewellery to stand the test of time then use a stone of harness 8–10 only. So it’s fair to say that even the very air we breathe slowly but surely damages gem materials with a hardness or 7 or lower. These quartz particles will abrade and damage any surface with a lower hardness. The dust in air by and large is made up of powdered quartz particles. Corundum, represented by both ruby and sapphire and some other hard exotic stones such as alexandrite, chrysoberyl and spinel. ![]() Our most popular are diamonds, which are the hardest naturally occurring mineral on the planet. We only sell stones of hardness 8 and higher. ![]() At Metal Urges we are in the business of providing our clients with the highest quality handmade jewellery possible. There are many gemstone collectors who would be up at arms at the statements in this paragraph. If a stone is expensive, beautiful but soft it becomes impossible to wear without damaging it. Mohs scale is related to the durability of a gem stone. Ten minerals have been selected for the scale-there are however many other gemstones that are represented through one of the Mohs ten.Ī gem stone by definition needs to be three things-durable, valuable and attractive. The scale is based solely on the ability of one gemstone to scratch another softer stone. For example, sapphires are two times harder than topaz, yet diamonds are around four times harder then sapphires. Mohs scale is an ordered scale only, in that there is no relation to the hardness of a consecutive pair of minerals to say that of the previous or next. Although quite an aged scale, Mohs scale is still used in the modern jewellery trade for describing hardness in gem material. In 1812 a German mineralogist by the name of Friedrich Mohs developed a scale of hardness based upon a harder minerals ability to scratch a softer one. Gemstone hardness – Mohs scale of mineral hardness ![]()
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