Sphene and Andalusite
Sphene is named from the Greek word for wedge, because of its typical wedge shaped crystal habit. It is also alternatively called titanite for its titanium content. Sphene can be cut as gems although it is considered a rarity on the gem market. It brings to the table a fire greater than diamond and unique colour shades. However its softness limits its desirability as a gemstone. Twinning is common in sphene and forms a classic twin shape that is found mostly in Pakistan. The twin is shaped like a deflated, caved-in football, only with flatter surfaces. Sphene can form nice crystals and can make a lovely addition to the collection of a collector who appreciates different crystal forms
Andalusite is named after Andalusia, the province of Spain where it was first discovered. Andalusite is pleochroic, i.e. it shows different colours in different directions. When cutting most pleochroic gemstones, such as iolite and tanzanite, the trick is to minimise the pleochroism and maximise the single best colour. With andalusite the opposite applies: cutters try to orient the gem to get a pleasing mix of colours: orange-brown and a yellowish green or gold. When they succeed, andalusite looks quite unlike any other gemstone, with patterns of colour dancing around the facets. The best colour play is seen in fancy shapes, particularly rectangular cushion shapes: in round cuts, the colours blend together. Andalusite is mined in Brazil and Sri Lanka.