Novo Horizonte, Bahia, Brazil

TiO₂

Crystal System: tetragonal
Colour: blood red, brownish yellow, brown-red, yellow, greyish-black, black, brown, bluish or violet
Lustre: adamantine, metallic
Habitus: prismatic to acicular crystals, rarely as equant dipyramidal individuals. Massive aggregates. Twinning is common, forming geniculated or reticulated aggregates (var. sagenite); contact twins with two, six, or eight individuals, cyclic, and polysynthetic
Hardness: 6 - 6½
Fracture: irregular/uneven, conchoidal, sub-conchoidal
Cleavage: distinct on {110}; less distinct or imperfect on {100} and {111}
Density: 4.25 g/cm³ 
Origin and geological occurrence: it is a common accessory mineral in magmatic and metamorphic rocks. It can be found in sedimentary rocks as a detrital component

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Samples:

4.13 Rutilo Twinned prismatic crystal in quartz with mica. Valais, Switzerland #oxides

4.14 Rutilo Prismatic crystals in quartz. Sierra Albarrana, Andalusia, Spain #oxides