I was wondering the same thing about the Grand Master material (entering an opaque stone). The design (page 44 in the newsletter) has a Material list: “Feldspar (Moonstone, Orthoclase, Labradorite, Plagioclase from Madagascar). Not sure why Madagascar plagioclase is so specific, maybe orthoclase? I have never seen a clear or even translucent Labradorite (which is a type of Plagioclase feldpar). Labradorite is one of my favorites and would be a nice looking opaque stone if it weren’t for the extensive coarse texture banding, cleavage steps and cracks. Hard to find a specimen that would be worthy of entry. I bet it would also be hard to judge with all the labradorescence flash and texture. I might just cut one for the heck of it for a practice piece. Could we get some official clarification on the entry of an opaque stone? Seems counter intuitive for a Grand Master entry.