Tourmaline Rubellite, cut to requirements

About Tourmaline:

Tourmaline occurs in a wide range of colors. It is one of the most favored gemstones for mineral specimens and cut gems collectors due to its incredible variety of colors and the beauty of its crystals.

Most tourmalines are known in the gem trade by the variety name following their color:

- Rubellite :Pink to red but also brownish, purplish or orangy, its color is usually due to manganese and iron.
- Verdelite :Yellowish green to bluish green, it is usually colored by iron.
- Indicolite: violetish to greenish blue.
- Paraiba: electric blue typical from Paraiba area in Brazil.
- Chrome tourmaline: Intense green color, own its color to chromium.
- Achoite: Colorless.

For the mineral collectors, tourmaline group varieties are better known by more scientific names dealing more with the composition and the structure of the stone:

- Dravite: typically yellow to brown can be red also.
- Schorl: Sodium and iron rich, Black.
- Elbaite: Sodium, aluminium, lithium rich, Many colors possible.
- Ferridravite: Magnesium and iron rich, Black.
- Chromdravite: Sodium, magnesium and chromium rich, Dark green.
- Buergerite: Sodium and iron rich, Bronzy brown.
- Liddicoatite: Calcium, Lithium, aluminium rich, many colors possible.

Highly saturated tourmalines with fine clarity will be highly priced with some exceptions, such as for Rubellite which even highly inlcuded can get high value.

Burma (Myanmar) is known for its fine tourmalines, which are mined in Mogok (most varieties), the Molo pegmatic area near Momeik is a lithium and beryllium rich pegmatite area that host very fine Schorl and exceptional fibrous "mushroom" like elbaites) and the Shan and Kayin states (green tourmaline). But most of the tourmaline commonly in the market is now coming from Brazil and Madagascar.

Tourmaline forms as a trigonal crystal in a variety of geological settings; as an associated mineral in metamorphic rocks as gneiss or schists, as long prisms in granitic pegmatites usually with a feldspar matrix, or as single crystals after alteration of the pegmatite resulting, for example, in kaolinisation. In these granite pegmatites it occurs in the immediate vicinity in the enclosing host rocks.

Pegmatitic tourmaline is commonly black and is associated with quartz and feldspar. The light colored gem tourmalines are much more rare, usually occurring in pegmatite core zones. Other occurrences for tourmaline are in hydrothermal veins where heated mineral bearing liquids or gases from deep igneous sources later cooled and crystallized along rock fractures, in granites due to late stage alteration of micas and feldspars by boron containing fluids, and by boron metasomatism in contact and regionally metamorphosed rocks. Some tourmaline bearing mica schists may have formed by regional metamorphism of argillaceous sediments containing evaporate borates. Because of tourmaline's relatively high hardness and specific gravity, it is often found in elluvial and alluvial deposits as for example in the gravels of Mogok in Burma or in those of Sri Lanka.

Learn more:
- Mindat.org