Gypsum     Red River Floodway, Manitoba, Canada.  5.4 x 3.5 x 3.5 cm ball with one excellent, gemmy swallowtail twinned crystal.  No damage.  This example is a complete floater (having no points of contact to matrix or anything else)  Views great from any direction.  This one is better than most small examples of this material.  These have become uncommon due to their not being mined for currently.  I think they are among the finest selentite gypsums available to the collector.   $60