eli5 What determines whether a gem is a sapphire, ruby, emerald, diamond, etc if those gems don’t necessarily have to be the most common thought color? For example, sapphires can be colors other than blue. What’s the difference between a red sapphire and a ruby?

Question

eli5 What determines whether a gem is a sapphire, ruby, emerald, diamond, etc if those gems don’t necessarily have to be the most common thought color? For example, sapphires can be colors other than blue. What’s the difference between a red sapphire and a ruby?

In: 5800

Answer 1

All gemstones are composed of different materials, or building blocks. These blocks are what determines what kind of gemstone you’re dealing with. Gems come in ‘families’ as well. Rubies and sapphires are both in the “corundum” family. Amethyst and citrine are both examples of the “quartz” family, though there are many, many other quartzes out there. Sometimes the family only has one type of gem in it, like diamond. While all these families are determined by what building blocks the gem is made of, very, very small amounts of other building blocks might change the color or special properties of the gem, and that determines where in the family tree it is.