There are many different types of “rocks” that exist. Which ones are considered a gemstone and why are they more precious than others?

A gemstone grows through natural processes, which eliminates all synthetic or lab-grown material. A gemstone is made up of mineral and organic material and has a particular set of characteristics unique to its specie and variety. In order to be considered a gemstone, a mineral must be beautiful, durable and rare. The most important of these three characteristics is beauty, which is defined by the colour, clarity, brilliance and light-reflecting qualities of the gemstone.

Durability is defined by the gemstone’s resistance to abrasion and breakage in order to be used in jewellery. The clarity and colour of a gemstone can be enhanced by procedures, or “treatments”, such as heat, irradiation, oiling, dyeing, and laser drilling. Although most gemstones require cutting and polishing to reveal their full beauty, some are formed perfectly by nature and require neither. An example of this is pearls and quartz crystals. The value of a gemstone is determined by its beauty, rarety, cut and polish, size as well as the market’s demand. Although some rocks may be very rare and old, such as meteorites, this doesn’t make them more valuable than a more commonly found stone that is in high demand.

The recovery of gemstones will also dictate their value. The process of extracting diamonds buried deep in kimberlite pipes will be more costly than panning for alluvial gemstones in river beds. Also, the mining of coloured gemstones is generally small-scale and production is driven by demand, versus diamond that is mined in large scale production. Some coloured gemstones’ value may be affected by the mining and exporting laws imposed by their country of origin. In Columbia, for example, open pit or surface mining is no longer permitted to extract emeralds. This means underground operations must be carried out, which is a more expensive and difficult procedure. Tanzanite faces a similar situation when it comes to the difficulty and cost of extracting the material.

If you are curious what the value of your gemstone is, visit a gemmologist. Not only are they knowledgeable on the value, origin, and characteristics of gemstones, they may also have interesting stories and curious lore about that particular stone.