more blue minerals
Amazonite is more green than blue, but more importantly, it is translucent, as are most silicates(at least in thin section). The color center is often expessed throughout the crystal but can also be zoned, like the crystal of Amazonite I've got on my desk right now. The basal parting surface shows a white core. Now that may be a compositional zoning or it may be a zoning due to depth of radiation penetration.
Azurite is another blue Copper mineral. Thing is, the copper signal on other spirit rocks has been unremarkable.
For Heinlein fans, a very blue mineral is Lazurite, AKA Lapis Lazuli.
Mind you, I'm not recomending that any of these particular minerals are in our rock in question, just making a list of blue minerals here.