The classic bright blue azurite from the Copper Queen Mine, circa late 1890s, wes world-reknowned at the time for this play of vibrant blue hues all mixed together. However, the unique aesthetics of this piece, which is very 3-dimensional and exhibits the lighter hue as a wave of color atop a previous generation of azurites, is absolutely unique to my experience. I have seen smaller versions of this style, or pieces showing this effect in a more random and less attractive manner, but none so dramatic as this one! What's more, it is pristine, absolutely without damage and complete all around - not bad for a piece this size, over 100 years old! The specimen was a "keeper" which is shown on his workbench, in the inside-cover shot in Gem & Crystal Treasures