Describing preciousness: COLOUR

Four words are often mentioned when diamond-shopping: colour, cut, clarity and carat.

Today we will consider colour. We all know what colour is, right? Red, blue, pink, pink plummy, mauvelicious, chocopop, crazy for coffee, super yellow hibiscus colour sensation, cheesy gland brilliant superstay, that sort of thing? Colours are great! But sometimes in fact colour can reduce the value of a thing.

Colourless diamonds are generally more valuable than those with a hint of tint. When diamond grading system was first introduced in the 1930s the only grades were A, B and C. So when they wanted to get a bit more complicated later in the century they started with grade D, “to avoid confusion”. Diamonds in grades D, E and F are the bestest and are described as colourless.

“Near colourless” or “white” diamonds are those in grades G-J. And those form K-Z are tinted, usually yellow or a yellowish brown. K, L, and M might appear white if set into a yellowish metal (like gold) but would look a bit yellow if you set them in a white one (white gold, platinum).

But to complicate things even further, when the tinting gets stronger and richer it becomes a feature rather than a fault, and the diamond starts becoming more valuable again. Red diamonds are pretty hot right now. (Don’t say you don’t want one, we know you are fibbing).

If you like colour instead of those boring albeit sparkly diamonds you need to go down the coloured stone store and pick yourself up some emerald, ruby, sapphire, spinel, tourmaline, topaz, citrine, or garnet. The colour of these gems is affected by small impurities within — for example, sapphire and ruby are actually the same basic mineral (corundum, or aluminium oxide) only sapphires contain trace amounts of titanium, vanadium and/or iron (creating a variety of colours, including blue, purple, yellow and green) and ruby contains chromium (reds and pinks). You know how one of the crowns in the Crown Jewels has a ruby the size of an egg on it? That’s called the Black Prince’s* ruby? It isn’t a ruby! It’s a spinel! Hahaha round one to spinel! (To be fair to gem-namers of yore, ruby and spinel are often found together and also you probably needed a bit of scientific gear to tell them apart).

Then you can get into further detail about their hue (colour), saturation (vividness or brightness) and tone (darkness/lightness). Allow plenty of time at the coloured stone store.

* The Black Prince was Edward III’s son and, confusingly, not Edward IV and not even a king. He was Prince of Wales though, and fought in a lot of battles and also was one of the founders of the Order of the Garter. What larks. He died a bit before Ed III so instead his brother Richard (II) became king afterwards. It is not clear why he was called the Black Prince; perhaps because he had a black shield or was a brute in battle.

The Black Prince's SPINEL on the Imperial State Crown. Nice, eh? Image from ruby-sapphire.com.

The Black Prince’s SPINEL on the Imperial State Crown. Nice, eh? Image from ruby-sapphire.com.

The Black Prince's Effigy, Cantebury Cathedral. Image from royalcentral.co.uk/

The Black Prince’s Effigy, Cantebury Cathedral. Image from royalcentral.co.uk/

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