Here we have a nicely trimmed crystallized quartz matrix hosting a 3 x 2.5 x 2 cm crystal of....FLUORITE! Looks like green topaz! Is it a twin? I do not think so...I THINK it is some weird octohedral modification. But it looks like green topaz. I just cannot get over it. Aesthetically, it is perhaps the most dramatic and shocking piece in the lot. In person, it is so gemmy and transparent that you can look righ tthrough it to your hand on the other side! It seems to be complete, although perhaps contacted smoothly, even around the backside. Yes, it is expensive. But, its amazing...