>>51221811Diamonds, unlike a lot of other gemstones, are made of one element - Carbon. Well, mostly, because the presence of other trace elements are what cause diamonds to have colour. A diamond that’s purely carbon would be clear and colourless. Also, what element is more “normal” than Carbon since it’s the glue of life as we know it?
This “elemental single-ness” and lack of colour indicating purity do work with the theme of Normal-types. Plus diamonds are basically the go to thing when you think of gemstones, which kind of helps solidify it as the Normal-type since this gimmick revolves around crystals.
I doubt not that much thought went into it, but it works pretty well if you engage your brain cell for a second.
