867 g, 17 pieces. $135/kg. Chalcopyrite, pyrite, and sphalerite on drusy quartz matrix from Kalimantan, Indonesian Borneo, small to medium sized pieces running roughly 1 to 3.5 inches.
Every piece is faced with a crust of small white to colorless quartz crystals, and the sulfides sit on top of that crust rather than under it. The chalcopyrite carries strong iridescence across most of the lot — electric blue and teal through violet, magenta, and bronze, with brassy gold showing where the color film is thin or absent. Pyrite appears as brighter, harder yellow crystals alongside it. Several pieces carry black sphalerite crystals up to about half an inch, glassy and well formed, and a few show cream to pale yellow mineral in the matrix beneath the quartz.
Coverage varies across the lot. Some pieces are densely peppered edge to edge, others carry the sulfides in looser scatter against more open quartz.
Every lot is filmed before it ships — what you see in the video is the material that arrives.
