Gemstones

Do you have interest in this stuff?

Star sapphires are quite interesting, for the way they make what would otherwise be a flaw, a highlight. The star in a star sapphire is simply an inclusion (usually titanium), which follows the underlying crystal structure (hence scattering out in six directions when looked at above). There is not really such a thing as a twelve pointed star sapphire, and what you’re actually seeing is two infusions that as the sapphire has continued to crystallise have been naturally superimposed. It’s not that uncommon for this to occur, but obviously far less common for the “needles” of the two inclusions to be so perfectly spaced. In fact, a lot of sapphires you see are technically star sapphires, but you simoly don’t see the star, because of the faceting. Just as you can hide many inclusions in diamonds by careful faceting, so you can hide inclusions in sapphires. The only way to show the inclusion is to cut the stone cabochon, rather than facet it. And obviously you only cabochon a stone where the inclusion will be aesthetically pleasing (and not all stars in sapphires are).

Well, obviously you would know what a star sapphire is. Or, at least, I certainly assumed you would. But there are probably many out there who know of them, but don’t realise what they are,

I used to work in a jewellers, and customers would come in and ask about star sapphires, believing them to be a completely different type of gemstone than a sapphire. Just as there were customers who don’t realise that there are different colours of sapphire. It’s weird, because they would know about different colours of diamond, but be surprised if we had a yellow or pink sapphire on display.

[EDIT] As you said yourself, learning never ends. It may have been the first time you had seen a twelve pointed star sapphire, and so it might likely be the first time anyone reading your post had, too. I was simply expressing my interest, and if someone learnt something, then that was cool. But it was hardly my intent.