This is a very large, FASCINATING specimen out of the Ed David collection, from Eastern Europe. It was in the Hoyt collection before Ed David got it. It features a big, rich cluster of hexagonal, poker-chip pyrrhotite crystals that were covered with a later generation of siderite (both are iron minerals that fed off the iron-rich solution in the pocket to grow). At the edge of the specimen is a patch of siderite crystals that grew densely on their own, to a larger size, next to the siderite-covered pyrrhotites.