Rubellite
Rubellite is the red variety of tourmaline, similar in colour to ruby, from which the name is derived. The most valuable stones have a colour similar to that of a 'good quality ruby'. Higher priced stones have a colour that is fairly consistent when viewed in daylight and artificial light. Less valuable stones turn brownish when viewed in incandescent light (from a filament light bulb).
Inclusions are common in rubellite and seem to appear more in stones with a darker hue.
Major source locations for rubellite include: Africa (Nigeria), Afghanistan, Brazil, Madagascar and USA (California)
Properties of the Gemstone and Additional Information
| Gemstone type: | A variety of the tourmaline group |
| Crystal System: | Trigonal |
| Chemical Composition: | A complex borosilicate of aluminium, magnesium, iron, calcium and alkali elements |
| Colour: | Deep pinkish-red colour or red that may have a brown or violet tint. |
| Lustre: | Vitreous |
| Pleochroism: | Dichroic: Strong in most stones, showing a variation in colour depth, but may be absent in others. |
| Dispersion: | Low |
| Hardness: | 7 to 7 1/2 on the Mohs' scale |
| Toughness: | Good, but may be damaged by thermal shock (sudden temperature change). |
| Cleavage: | Very uneven |
| Density in gm/cc: | 3.0 to 3.1 |
| Double refraction: | Yes |
| Refractive index: | 1.62 to 1.64 |
Common Treatments
Tourmalines may be heat-treated or irradiated to improve their colour. Treated stones are normally stable, but when subject to prolonged exposed to heat or strong light, they may fade.