(1) With sphalerite , it is one of the rarest minerals of the pillow basalts.(2) Black sphalerite is found within the gold-quartz vein and in the adjacent country rock.(3) Marmatite is the black, high-iron variety of sphalerite .(4) Most of the sphalerite in the Eagle mine is marmatite, the black iron-rich variety.(5) The crystals are perched on quartz along with rosin-colored sphalerite showing the black tarnish reported by Hurst.
