By David Moncrief
While it might seem that all gemstones sould be classified as rare and precious, you will probably find them most often referred to as precious and semi-precious. What's the difference? Nothing really. However, it would seem that the top four (4) gemstones - diamond, emerald, ruby and sapphire - are most often considered 'precious' with the remaining 120+ gemstones falling into the category of 'semi-precious'. And, while any one of the top four gemstones could sell for less than a semi-precious if it were considered 'inferior'; there are some highly valued 'semi-precious' gemstones, i.e, Pariaba Tourmaline and Alexandrite to name two (2) that could easily sell for many times more than a 'clean' precious gemstone.
Different gemstones have different hardness factors. This property is based on the Mohs scale measuring from 1 - 10. With a diamond being 10 (the hardest) and 1 being the softest. Soft gemstones - those ranging from 1-5 on the Mohs scale are best suited for earrings, pendants or rings that are ocassionally worn. Medium to hard gemstones - those ranging from 6 - 9 on the Mohs scale are suited to almost any type of jewelry. Hard gemstones - those receiving a 10 on the Mohs scale - are well suited for everyday wear in all types of jewelry. These 'hard' gemstones include Diamonds, Sapphires and Ruby.
Another consideration when purchasing a gemstone is its tendency to fracture due to temperature change. This change in temperature can be from exposure to hot water, going from inside to outside or vice versa where there is a significant temperature difference, exposure to intense light (tanning bed) or simply going from one room to another . . . depending on the sensitivity of the gemstone. Some of the gemstones that fall into this category are Apatitie, bi- and tri-color Tourmaline and Opals.
The chart below will give you an overview of some gemstones along with their hardness and toughness. A gemstone may be hard but not tough, i.e, how easily a gemstone cracks or chips.
The chart below will give you an overview for some of the more common gemstones with regards to hardness and their tendency to fracture (TF). We have used a scale of 1-3 for indicating a gemstones tendency to fracture with 1 representing a gemstone that is 'very likely to fracture'; 2 representing a gemstone that is 'possibly likely to fracture'; and 3 representing a gemstone that is 'not likely to fracture'.
** User understands and accepts all policies associated with use of this page and any procedures. View policies.