Rutile and zircon. Richards Bay, Republic of South Africa
This is a concentrate from a beach placer. Zircon (grey) shows complex zoning seen as slight reflectance differences (centre bottom), and faint internal reflections (centre top). Rutile grains (light grey) are euhedral (bottom left) to rounded (top right) and some show poor polishing due to the strong (110) cleavage of rutile (top left, bottom right).
Grain mount, plane polarized light, x 80, air