Accessory · Biaxial (+)
Titanite (sphene) in thin section
Yellow-brown with very high relief and extreme birefringence (about 0.10–0.16). Wedge-shaped (lozenge) cross sections make it easy to recognize.
Plane-polarized light
| Color | Brown, Yellow |
|---|---|
| Pleochroism (color change on rotation) | Weak, Strong |
| Relief | Very high |
| Cleavage | None |
| Shape | Euhedral |
Cross-polarized light
| Maximum birefringence | about 0.130 |
|---|---|
| Highest interference color | Creamy high-order |
| Extinction | Inclined |
| Twinning | Simple (two halves), None |
Interference colors are often masked by the mineral's own color.
Telling it apart
Extreme birefringence gives upper-order white interference colors, unlike other brown minerals here.
Where you'll find it
Granodiorite, syenite, amphibolite
Photo examples
Alex Strekeisen · Search Wikimedia Commons
Photos open on the source sites.
Identify an unknown grain Read interference colors Practice mineral ID
Related minerals
Sources
OpticMin, ATHENA, Univ. of Geneva (P. Perroud) · Alex Strekeisen thin-section collection · Distinguishing features of minerals (UT Arlington) · MIT OCW 12.109 amphibole lab · SEPM Strata: carbonate staining · Wikipedia mineral pages (infobox optical data) · Athabasca University rocks and minerals · Smith College petrography: perthite