A gemstone is a precious stone, that is, a mineral that when cut and polished can be used in the manufacture of jewelry or any other type of decorative ornament. Among the best known gemstones we can highlight the following: opal, sapphire, topaz, azurite, agate, diamond or turquoise. Gemology
Certain gemstones are of organic origin, such as natural pearls and corals. All of them have some common characteristics: a certain beauty , a striking color, a degree of transparency and an intensity in their shine. The scientific discipline that studies gemstones is gemology.
gemology as a science
This discipline is relatively recent, as it was the 20th century when the first academic institutions in this area of knowledge appeared . Gemology is integrated into a more general area, mineralogy, which in turn is a branch of geology. Gemology
Although based on theoretical principles, in practice, it is intended for the business world, more specifically for the ornamentation or jewelry sector.
Gemologists use their own instruments, which are quite different from those used by geologists. In this sense, tools are used so as not to damage or deteriorate the precious stones.
Gemologists look at the different physical and optical properties of gemstones. Thus, each stone or gem has its specific weight , its color, its refractive index, its type of spectrum or its level of hardness.
The hardness of the gems
In addition to the beauty, color or shine of gemstones, gemologists study the hardness of gemstones. This property does not simply refer to the possibility of breaking these pieces with greater or lesser difficulty, but rather to the resistance to scratching . To measure this property, it uses the so-called scale Mohs.
This scale objectively describes the hardness of a gemstone. For this, a table from 1 to 10 is established, where the number 1 indicates a minimum degree of hardness and 10 a maximum degree. Gemology
Each gemstone can be compared with another using the following table of equivalences:
Level 1 is represented by talc, 2 corresponds to gypsum, 3 to calcite, 4 to fluorite, 5 to apatite, 6 to orthoclase, 7 to quartz, 8 to topaz, 9 to corundum and, lastly, the 10 with the diamond.
Talc has a lower hardness as it can be scratched with a fingernail. Apatite is level 5 and can be scratched with difficulty with a piece of steel, whereas diamond is scratched only with specialized tools. Gemology