Copper replacements of azurite from this small mine are world-famous for their uniqueness and form. However, they are very rare, and frankly usually not all that sharp in crystal form (due to both nature's lack of fidelity in replacing azurite by copper, making the edges rounded; and wear over time). I am told that many are quite old, certainly pre-1960s. Of all that I have seen and handled, this piece has the sharpest, best preserved crystals. It was formerly in the noted collection of Bob Jones, who is now the senior editor of Rock and Gem Magazine. Due to its superb qualities relative to the others I have seen, I do value this veryhighly. To me, it stands way above the crowd. As well, its a helluva interesting replacement that you do not find elsewhere.