Ping Wu has produced literally tonnage value of cassiterite over the last 12 years or so. And I have seen and handled thousands of specimens from here. Most cassiterites are twinned to some degree, creating complex but beautiful crystals in cluster and singly. This is untwinned, much more rare it seems. However, I cannot recall holding a single cassiterite crystal that impressed me as much for form and symmetry as this fine miniature. It is not even super expensive - it is just super fine, so sharp it looks carved or casted. It is so jet black and so perfectly smooth that you can see hints of fingerprints in the photos, just from the quick handling of the piece, as the oils dull its natural luster (in contrast to so many minerals where disreputable dealers add oil to enhance luster!). If you collect Chinese minerals, I could think of no better addition for a miniature suite, than this sharp crystal.