Heazlewoodite, millerite, nickel arsenide. Unst, Shetland Islands, Britain
125µm
Heazlewoodite (white, centre), the main phase, encloses a small rounded crystal of nickel arsenide (pink, lower reflectance, centre left) and is altered along fractures and grain boundaries to millerite (light yellow-brown, lower reflectance, centre right). Black areas are serpentine.
Polished thin section, plane polarized light, x 160, oil
