Unknown origin

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Showing 273–288 of 342 results

  • Spinel

    Spinel

    2,202 ct. | V/C
    GLA
    €900.00
  • Spinel

    Spinel

    2,289 ct. | VII/A
    GLA
    €500.00
  • Spinel

    Spinel

    1,998 ct. | V/A
    GLA
    €900.00
  • Spinel

    Spinel

    2,565 ct. | VI/C
    GLA
    €1,000.00
  • Spinel

    Spinel

    4,243 ct. | VII/C
    GLA
    €2,000.00
  • Spinel

    Spinel

    3,883 ct. | VII/B
    GLA
    €1,800.00
  • Spinel

    Spinel

    2,173 ct. | VI/C
    GLA
    €1,000.00
  • Spinelle

    Spinelle

    3,241 ct. | IV/C
    50943
    €3,600.00
  • Tanzanite

    Tanzanite

    19,235 ct. | IV/A
    GLA
    €18,000.00
  • Topaz

    Topaz

    85,770 ct. | VIII/A
    GLA
    €2,600.00
  • Topaz

    Topaz

    86,318 ct. | VII/B
    GLA
    €2,400.00
  • Tourmaline

    Tourmaline

    4,159 ct. | IV/C
    GLA
    €900.00
  • Tourmaline

    Tourmaline

    4,742 ct. | IV/C
    GLA
    €1,000.00
  • Tourmaline

    Tourmaline

    5,035 ct. | IV/C
    GLA
    €1,000.00
  • Tourmaline

    Tourmaline

    5,277 ct. | IV/C
    GLA
    €1,500.00
  • Tourmaline

    Tourmaline

    5,463 ct. | IV/C
    GLA
    €1,300.00

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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