Its not just the sharp edges Juno, the primary stones have a lot more inclusions & are more opaque, are also a lighter more pinkish color, and as you say are sharper & flatter, so the smaller stones are useless to use as gems, even with treatment.
MUS's secondary stones are all more rounded as you say. I was reading how secondary are generally the larger, more stronger stones, and so break away from the host rock, then get ground down and smoothed over the millenniums by their movement through the sediment beds. They also have more chromium in them and generally (not always) are of stronger colour & clearer than primary stones.
MUS Price at posting:
15.0¢ Sentiment: Buy Disclosure: Held
