Sphalerite, Zinc sulphide, (Zn,Fe)S. Dylife mine, Central Wales Orefield. Brecciated rock from ore deposits, consisting of light grey country rock, possibly limestone with sphalerite in massive form. Also very fine druzy quartz and very minor galena. The sphalerite is overlying the quartz in several places, indicating that the sphalerite was a later deposit.