Gems are one of the most intriguing items of collection. For centuries, they have been extracted from deepest crevices and darkest caves. There are many ways of classifying the gemstones. Most of the gemstones belong to the family of minerals which are classified as per their chemical composition, crystalline structure and presence of impurities.
Here is a smart list of principles about how gemstones are generally classified.
- Minerals and Non-mineral gemstones
Mineral gemstones are more popular and commercially acceptable classification. Non-mineral gemstones are placed in the minority list owing to their organic nature. For example, the non-mineral gemstones include:
- Sea Coral
- Petrified Wood
- Petoskey stone
Pearl, obviously is the most fascinating non-mineral organic gemstone in the list.
From a collector’s point of view, this is the most basic classification of gemstones. It is not that hard to identify an artificial gemstone from the natural ones if you understand the physical properties well. Artificial are often placed in the categories of refined, treated gemstones. Owing to the improvement in technology and chemical products, it could be a difficult task to distinguish between an artificial and natural stone if you are buying it for the first time.
Some of the popular artificial/ synthetic gemstone varieties belong to:
- Cubic zirconia
Artificial varieties of sapphires, garnets, alexandrite, rubies and peridots are also available which can be distinguished based on UV radiation tests and hardness tests.
Based on the chemical composition of the gemstone, they are classified under the following categories:
- Rocks and non-rocky gemstones
Some gemologists prefer to classy the gemstones as minerals and rocks. It is very similar to the non-mineral gemstone classification but includes only rocky constituents. Some of the most common rocky gemstones listed in the general classification are:
- Lapis lazuli
For example, lapis lazuli is classified as a rock as well as a semi-precious gemstone. The blue coloured stone is extracted from the mines in Pakistan, Afghanistan, Chile, Italy and Russia. Soapstone is also a metamorphic rock used for making steatite scarabs.
- Precious and Semiprecious
Since 10th century AD, the gemstones are classified as precious and semi-precious items. Anything that demands a price tag of USD 100 per carat is precious. Depending on the gloss, flawless engineering and appeal, a precious stone can fetch higher price. It is a very crude way of classification though. Some semi-precious stones are prized at USD 1000 and above.
Semi-precious gemstones include:
- Rose Quartz
- Black onyx
There are many trade commission agencies around the world that now penalize the manufacturers of gemstone when they use the term ‘semi-precious’.