Watermelon Tourmaline

Big Photo

Namibia
33.15 carats
© Palagems

A variety of Tourmaline with colour zoning showing a pink core and green edges.

Watermelon Tourmaline Gemstones by Colour

This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
 

Watermelon Tourmaline Gemstones by Size

This table shows distribution of Watermelon Tourmaline gemstone sizes that are listed on this site. This can give a good indication as to the general availability of this gemstone in different sizes.
Contributed photos
Lightest:4.1 cts
Heaviest:33.15 cts
Average:12.62 cts
Total photos:4
Do you have a larger Watermelon Tourmaline? Why not upload a photo?
4.10ct to 7.01ct7.01ct to 9.91ct9.91ct to 12.82ct12.82ct to 15.72ct15.72ct to 18.63ct18.63ct to 21.53ct21.53ct to 24.44ct24.44ct to 27.34ct27.34ct to 30.25ct30.25ct to 33.15ct
General Information
A variety or type of:Tourmaline
Chemical Formula
Na(Li
 
1.5
Al
 
1.5
)Al
 
6
(Si
 
6
O
 
18
)(BO
 
3
)
 
3
(OH)
 
3
(OH)
Gemdat.org, Management Team (2012) Formula given for elbaite. Most, but not all, watermelon tourmaline is elbaite.More from other references
Photos of natural/un-cut material from mindat.org
Physical Properties of Watermelon Tourmaline
Mohs Hardness7 to 7.5
Gemdat.org, Management Team (2012)
Specific Gravity2.90 to 3.40
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
TenacityBrittle
Gemdat.org, Management Team (2012)
Cleavage QualityNone
Gemdat.org, Management Team (2012)
FractureUneven,Irregular,Conchoidal,Sub-Conchoidal
Gemdat.org, Management Team (2012)
Optical Properties of Watermelon Tourmaline
Refractive Index1.614 to 1.666
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical CharacterUniaxial/-
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Birefringence0.014 to 0.040
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Dispersion0.017
Arthur Thomas, Gemstones (2009)
Colour
Colour (General)Green rims on red/pink cores
Gemdat.org, Management Team (2012)
TransparencyTransparent
Gemdat.org, Management Team (2012)
LustreVitreous
Gemdat.org, Management Team (2012) Sub-Vitreous
Fluorescence & other light emissions
Fluorescence (Short Wave UV)The red/pink cores may fluoresce chalky blue or creamy white depending on the activator. Sometimes specimens show both colors in patchy or zonal arrangement.
King, Vandall T., Worldwide Tourmaline Responses to SW and LW UV Light (2009) Mineral News
Crystallography of Watermelon Tourmaline
Crystal SystemTrigonal
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
HabitPrismatic to acicular crystals
Michael O’Donoghue, Gems, Sixth Edition (2006)
Further Information
Mineral information:Watermelon Tourmaline information at mindat.org
Significant Gem Localities
Brazil
 
  • Minas Gerais
    • Coronel Murta
      • Barra do Salinas
Cassedanne and Roditi (1996)
USA
 
  • California
    • San Diego County
      • Mesa Grande Mining District
        • Gem Hill
Fisher, J. 2002. Gem and rare-element pegmatites of southern California. Mineralogical Record, Volume 33, Number 5: pages 390-396, photographs.
  • Maine
    • Oxford County
      • Newry
Freeman (2005)
      • Paris
Freeman (2005)
Copyright © Jolyon & Katya Ralph 1993-2019. Site Map. Locality, gem & photograph data are the copyright of the individuals who submitted them. For more information please contact the . Gemdat.org is an online information resource dedicated to providing free gemmological information to all.