Behind The Gems: Gemstone Basics

“Behind the Gems” is a long-running monthly series that takes you on an exclusive, behind-the-scenes tour of our signature collections.

In our previous articles, we mentioned a few of the things you should know before purchasing gemstones and what to look for when evaluating them. So you may already be familiar with carats and what they mean in the jewellery world. But there is more than size and weight to consider.

In addition to the physical dimensions of a gem, we need to consider its intrinsic and its intangible characteristics. On the one hand, there’s durability and beauty. On the other, rarity and demand.

In jewellery terms, durability refers to a material’s ability to withstand wear, scratching and exposure to chemicals (i.e. its structural stability). The more it can withstand, the more valuable it is. In order to compare them, materials are often placed on the Mohs scale of hardness. Diamonds are way up top at 10, as they are the hardest naturally occurring gemstone - they can only be scratched by other diamonds. In practice, this means that they are can be used in any type of jewellery.

Pearls, or course, are at the lower end of the scale (between 2.5 - 4.5 Mohs). As they absorb moisture and scratch relatively easily, they shouldn’t come in contact with water or rough surfaces too frequently. In practice, they are better suited to be worn as earrings or necklaces as opposed to rings.

When it comes to beauty… well, it's subjective. Is ruby red more valuable than raspberry red? It depends on the buyer. Still, there is an objective metric for comparing samples of the same type. Namely, how light moves through the material. This is described as sparkle, brilliance, fire or lustre and is linked to the purity of the stone. Generally, the clearer (and purer) the gem, the more valuable it is.

Then, the harder a stone is to find or mine, the more it is valued. Rarity is usually a constant, predictable factor. However, there have been spectacular turnarounds. Amethyst was considered a rarity up until the 19th century, when a large deposit was discovered in Brazil, leading to a significant drop in price and perceived value.

Finally, there’s demand, the most volatile of factors. Diamonds are now forever - but they’ve only been so since the De Beers campaign in the 1930s. Pearls are the staples of classic styling. But they can quickly read old-fashioned unless you wear them in a contemporary way.