Sphene, also known as titanite, is a rare calcium titanium silicate mineral with the chemical formula CaTiSiO5. It is prized for its exceptional brilliance, fire (dispersion), and vibrant colors, making it a popular gemstone among collectors and enthusiasts.

Key Characteristics:

1. Color: Sphene comes in a variety of colors, including yellow, green, brown, gray, and even orange or reddish shades. Its color is influenced by trace elements like iron and rare-earth elements.

2. Luster: It exhibits a vitreous to adamantine luster, adding to its visual appeal.

3. Fire (Dispersion): Sphene has a higher dispersion than diamond, meaning it can exhibit a rainbow-like play of colors under light.

4. Hardness: It has a Mohs hardness of 5 to 5.5, making it relatively soft for use in jewelry that may be exposed to wear.

5. Transparency: Sphene can range from transparent to translucent, depending on the quality.

6. Crystal System: It crystallizes in the monoclinic system, often forming wedge-shaped crystals.

7. Birefringence: Sphene has strong birefringence, resulting in a doubled appearance of its back facets when viewed under magnification.

8. Origin and Occurrence: Sphene is found in metamorphic rocks, pegmatites, and granite formations. Notable sources include Brazil, Madagascar, Pakistan, Sri Lanka, and the United States.

Uses:

• Jewelry: Though not suitable for everyday wear due to its softness, sphene is used in fine jewelry, especially for earrings, pendants, or display pieces.

• Collector’s Gemstone: Its rarity and unique optical properties make it highly sought after by gem collectors.

Sphene’s stunning beauty and optical properties, combined with its scarcity, make it a truly fascinating gemstone.