GIA's Gübelin Gem Project: Tourmaline

Tourmalines have a very complex chemical composition, and more than a dozen mineral species are recognised within this group. Their highly variable chemical composition gives rise to a wide range of colours. Among the many varieties of elbaite tourmaline are verdelite (green), indicolite (blue) and rubellite (red). Some tourmaline specimens display multiple colours. Optical effects include pleochroism (a change of colour when the gemstone is rotated) and chatoyancy (a “cat’s-eye” seen in reflected light).

 

35039 13.31 ct tourmaline (dravite) Kenya (PDF)	34461 4.17 ct tourmaline (dravite) Mexico (PDF)	33635 31.21 ct tourmaline (dravite) Mozambique (PDF)
34666 3.24 ct tourmaline (dravite) Myanmar (PDF)	35064 10.36 ct tourmaline (dravite) Tanzania (PDF)	33648 12.33 ct tourmaline (elbaite) Afghanistan (PDF)
33604 4.52 ct tourmaline (elbaite) Brazil (PDF)	33617 7.23 ct tourmaline (elbaite) Brazil (PDF)	33606 8.01 ct tourmaline (elbaite) Brazil (PDF)
34310 13.27 ct tourmaline (elbaite) Brazil (PDF)	34309 16.87 ct tourmaline (elbaite) Brazil (PDF)	34311 20.15 ct tourmaline (elbaite) Brazil (PDF)
34379 3.36 ct tourmaline (elbaite) Kenya (PDF)	33624 3.68 ct tourmaline (elbaite) Kenya (PDF)	33683 6.53 ct tourmaline (elbaite) Madagascar (PDF)
34507 7.13 ct tourmaline (elbaite) Mozambique (PDF)	34531 7.50 ct tourmaline (elbaite) Mozambique (PDF)	33612 8.05 ct tourmaline (elbaite) Mozambique (PDF)
34524 12.87 ct tourmaline (elbaite) Mozambique (PDF)	34526 16.08 ct tourmaline (elbaite) Mozambique (PDF)	34229 31.48 ct tourmaline (elbaite) Mozambique (PDF)
34492 48.86 ct tourmaline (elbaite) Mozambique (PDF)	34668 11.59 ct tourmaline (elbaite) Myanmar (PDF)	34239 5.57 ct tourmaline (elbaite) Namibia (PDF)
34724 7.55 ct tourmaline (elbaite) Namibia (PDF)	34726 10.00 ct tourmaline (elbaite) Namibia (PDF)	33629 11.62 ct tourmaline (elbaite) Namibia (PDF)
34750 3.61 ct tourmaline (elbaite) Nepal (PDF)	34749 5.50 ct tourmaline (elbaite) Nepal (PDF)	33589 21.57 ct tourmaline (elbaite) Nepal (PDF)
34945 11.60 ct tourmaline (elbaite) Sri Lanka (PDF)	34245 4.88 ct tourmaline (elbaite) The United States (PDF)	33619 8.37 ct tourmaline (elbaite) Zambia (PDF)
33585 40.08 ct tourmaline (elbaite) - achroite Brazil (PDF)	33591 4.80 ct tourmaline (elbaite) - achroite The United States (PDF)	33679 3.88 ct tourmaline (elbaite) - indicolite Namibia (PDF)
33672 7.25 ct tourmaline (elbaite) - indicolite Namibia (PDF)	34728 9.19 ct tourmaline (elbaite) - indicolite Namibia (PDF)	34729 9.88 ct tourmaline (elbaite) - indicolite Namibia (PDF)
33671 1.80 ct tourmaline (elbaite) - indicolite Russia (PDF)	35202 7.13 ct tourmaline (elbaite) - indicolite The United States (PDF)	34500 11.41 ct tourmaline (elbaite) - rubellite Mozambique (PDF)
34721 5.75 ct tourmaline (elbaite) - rubellite Namibia (PDF)	35203 14.63 ct tourmaline (elbaite) - rubellite The United States (PDF)	33588 16.84 ct tourmaline (elbaite) - rubellite The United States (PDF)
33658 12.33 ct tourmaline (elbaite) - verdelite Afghanistan (PDF)	33665 6.02 ct tourmaline (elbaite) - verdelite Namibia (PDF)