Sphene, also known as titanite, is a captivating gemstone distinguished by its remarkable brilliance, diverse color palette, and unique optical characteristics.
A Spectrum of Vibrant Hues
Sphene exhibits a wide array of colors, often displaying a fiery play of light due to its high dispersion. Its colors can range significantly, offering options from subtle to intensely vivid:
- Yellow
- Red
- Brown
- Brownish
- Yellowish green
- Green
- Black
This broad spectrum allows sphene to appeal to various tastes, with the green and yellowish-green varieties often being highly sought after for their intense color and sparkle.
Distinctive Crystal Shape and Optical Phenomena
The name "sphene" itself offers a clue to its appearance, being derived from a Greek word meaning "wedge," which refers to the typical wedge-shaped form of its crystals. This distinctive crystal habit is one of its identifiable features.
Beyond its color and shape, sphene is renowned for its exceptional optical properties, particularly its high birefringence. Birefringence is an optical property where light entering the crystal is split into two rays traveling at different velocities, causing a noticeable visual effect. In sphene, this high birefringence results in the doubling of facet junctions, meaning that when you look through the stone, the edges where its facets meet appear as blurred or double lines rather than sharp, single lines. This unique doubling effect adds to sphene's distinct and attractive appearance, giving it a somewhat "fuzzy" or "sleepy" look from certain angles, which gemologists often use as an identifying characteristic.
