Crystal Mines cannot be built

[Knight of Virtuosity]

I have the technology, I have the income. What am I lacking? It does not show in the buildable options.

[galadon3]

Does the planet have the ressource? Those rare ressources need the feature on the planet.

[Fartikus]

You need to have a planet with the special modifier for it. Very few planets have the modifier for crystal mines. It's like Betharian mines.

[Knight of Virtuosity]

OK, thanks.

[Shad]

What you want is refinery building you get later, these can be built anywhere.

[Knight of Virtuosity]

Yes, figured it out, it is called Synthetic Crystal Plants. These produce the Rare Crystals from Minerals, later tech.