Description
FACTS
properties of tourmaline
- Separate mineralogical group with many varieties
- Hardness grade 7 – 7,5
- Chemical formula: XY3Z6(T6O18)(BO3)3V3W(V, W, X, Y, Z stand for different possible elements)
- Includes all colors
- Colored by different metal oxides
- Specific gravity 2.8 – 3.3 g/cm3
origin
- Brasilia
- Madagascar
- Pakistan
- Various locations in Europe
- Mozambique
- Namibia
- Nigeria
worth knowing
- Oldest known locality in modern trade: Brazil
- Occurs in all colors
- Forms beautiful crystals with very good crystal endings
- Various esoteric and healing meanings
- Also large crystals and large cut stones possible
- The locality Pakistan was discovered only around 2010
investment in tourmaline
- Still undervalued compared to other gemstones.
- Exception: the Paraiba tourmaline, which can be more expensive than sapphire
- Stones should be at least 5 ct in weight, except for Paraiba
- Larger stones have higher appreciation
- Experts calculate 6 – 8% increase in value per year
- Beautiful, pure stones with clear colors are preferable
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