[Aracelis]

Damn! Spherulites? Ooids? Pisoliths? What I wouldn't give for a thin-section of these things. Could be volcanic glass, quartz, or calcium carbonate. If CaCO₃, then we may be looking at the bottom of an ancient body of water.

[Fitzcarraldo]

What I wouldn't give for a thin-section of these things.

I think I see some spheres that have been split in half because they are round and don't exhibit the "limb darkening" of a full sphere...