Verdelite gemstone information (original) (raw)
Verdelite is probably one of the most common and used gemstones available in the market today. The mineral is dark green in color, though it is sometimes seen in a light green or light brown shade.
| General Information | |
|---|---|
| A variety or type of: | Tourmaline |
| Other Names/Trade Names: | Verdelith |
| Chemical Formula | Na(Li 1.5Al 1.5)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH), Management Team (2012) Formula given for elbaite. Most, but not all, verdelite is elbaite. |
| Verdelite Treatments | |
| Routinely heat-treated to lighten the color - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 5 | |
| Physical Properties of Verdelite | |
| Mohs Hardness | 7 to 7.5Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
| Specific Gravity | 2.90 to 3.40Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
| Tenacity | BrittleMichael O?Donoghue, Gems, Sixth Edition (2006) |
| Cleavage Quality | IndistinctWalter Schumann, Gemstones of the world (2001) |
| Fracture | Sub-ConchoidalArthur Thomas, Gemstones (2009) |
| Optical Properties of Verdelite | |
| Refractive Index | 1.614 to 1.666Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
| Optical Character | Uniaxial/-Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
| Birefringence | 0.014 to 0.040Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
| Pleochroism | Strong: dark green - yellow-greenWalter Schumann, Gemstones of the world (2001) |
| Dispersion | 0.017Walter Schumann, Gemstones of the world (2001) |
| Colour | |
| Colour (General) | GreenHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
| Transparency | Transparent,Translucent,OpaqueUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
| Lustre | VitreousArthur Thomas, Gemstones (2009) |
| Crystallography of Verdelite | |
| Crystal System | TrigonalHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
| Habit | Prismatic to acicular crystalsMichael O?Donoghue, Gems, Sixth Edition (2006) |
| Further Information | |
| Mineral information: | Verdelite information at mindat.org |
| Significant Gem Localities | |
| Afghanistan Nuristan Kamdesh District PaprokGlas (2002)Brazil Minas Gerais Coronel Murta Barra do Salinas DistrictCassedanne and Roditi (1996) São José da SafiraMenezes (2009)Mozambique Zambezia Province Gilé District Muiane-Naipa group Muiâne pegmatite (Muiâne mine; Emdal mines)Henn and Bank (1997) Naipa mineHenn and Bank (1997) Nanro Pegmatite (Nacuissupa Pegmatite; Naquissupa Pegmatite)Schafer and Arlt (2000)Sri Lanka Sabaragamuwa Province Ratnapura District Ratnapura Gem gravelsTajikistan Gorno-Badakhshan Rangkul' Highlands Rangkul' pegmatite fieldSkrigitil (1996)USA California San Diego County Pala Mining District Pala Tourmaline Queen Mountain (Pala Mtn; Queen Mtn) Stewart MineFisher et al. (1999) Warner Springs Mining District Warner Springs Cryo-Genie Mine (Cryogenie Mine; Cindy B-Cryogenie claim; Lost Valley Truck Trail prospect)Laurs (2001, 2002, 2004) Maine Oxford County Newry Dunton Gem QuarryFreeman (2005) |