Rutile. Richards Bay, Republic of South Africa
110µm
This is a concentrate from a beach placer. Rutile grains show strong internal reflections (red, centre top) in some grains but few reflections in others. Both simple twins (bottom left) and polysynthetic twinning (centre top) are clearly visible due to the strong anisotropy of rutile.
Grain mount, plane polarized light, x 180, oil
