Titanite is a rare titanium mineral that occurs as an accessory mineral in granitic and calcium-rich metamorphic rocks. It is a minor ore of titanium and a minor gemstone known as "sphene." Titanite's diagnostic properties are its crystal habit, colour, and lustre. Its monoclinic crystals are often wedge-shaped or tabular-shaped. Its typical colour range is yellow, green, brown, and black. Pink, orange, and red specimens are rare. Titanite has a resinous to adamantine lustre that is rarely seen in other minerals. It has one of the highest dispersions of any mineral - significantly higher than diamond. Titanite is also pleochroic. Transparent specimens might show its three trichroic colours. Titanite is sometimes confused with sphalerite, especially when observing an adamantine to resinous lustre. Sphalerite is softer than titanite, and often produces an odour of sulphur immediately after a streak test - "".