Understanding Gemstones

Janine is fascinated by the organic nature of gemstones, the ingrained colours and striations created over millions of years which give each individual stone its inner fire and raw intrinsic beauty. After 26 years of working with jewellery she feels its time for an easy to understand approach to gems – without the need for a degree in gemology! So here’s some information about these miracles of nature.​

All precious and semi-precious stones have something special and beautiful about them. Value is given to gemstones according to availability, aesthetics, colour, transparency, lustre, and hardness. Semi-precious stones often refer to softer stones of less value, as opposed to precious stones which are harder and have more value. This terminology however, is not entirely correct as many “semi-precious” stones are more valuable per carat than “precious” stones. It would be better to refer to them all as “gemstones”.

Since the beginning of time, Gemstones have been measured in “carats”. In ancient times the term was derived from the use of Carob seeds from the Carob tree, to measure gem weights (very much like the “foot” measurement). A more metric way of measuring stones is by points i.e. there are 100 points in a carat, so a 0,50ct (50 pointer) is half a carat, a 0,25ct (25 pointer) is a quarter carat, and gemstone prices are often priced “per carat”.

Availability of gemstones is not always as straight forward as what is being mined at the time. In some cases the “availability” of gemstones is controlled or ”managed”. For example, the value of a red garnet (pyrope garnet) is less than an orange garnet (spessartite). This is because the orange garnet is far less common, plus it has the added value of an intense orange colour that is highly sought after.