Haematite, TiO2 minerals and zircon. Bridgnorth, Britain
250µm
A rounded zircon (light grey, centre top) is zoned. Haematite (blue-white) occurs as very poorly polished fine-grained intergrowths cementing silicate grains (low reflectance, right top and bottom); as rounded martite grains pseudomorphing magnetite (centre right) and as single coarse-grained crystals (top centre, bottom left). TiO2 minerals took similar to haematite, but their reflectances are slightly lower and they have pink-grey surface colours. The coarse oxide cementing quartz grains (bottom right) is haematite, whereas that cementing quartz (top right) is TiO2. An equant grain of primary iron-titanium oxide (centre left) has been pseudomorphed by a fine-grained intergrowth of haematite and TiO2 and is enclosed within a single authigenic crystal of haematite.
Grain mount, plane polarized light, x 80, air
