Andalusite Gemstones by Colour
This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
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Andalusite Gemstones by Size
This table shows distribution of Andalusite 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:0.57 cts
Heaviest:3.92 cts
Average:1.92 cts
Total photos:27
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| General Information | |||||||||||||||||||||||||
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| Varieties/Types: | Viridine - A manganese-bearing, green Andalusite. | ||||||||||||||||||||||||
| Chemical Formula |
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| Andalusite Treatments | |||||||||||||||||||||||||
| It is reported that olive-green material from Brazil changes to pinkish when heated (Sinkankas, 1972), while brown material is reported (Smith et al, 1978) to fade above 800°C to colorless. Irradiation could conceivably reverse these changes (Nassau, 1984 | |||||||||||||||||||||||||
| Physical Properties of Andalusite | |||||||||||||||||||||||||
| Mohs Hardness | 7.5, Blue Chart Gem Identification (2010) More from other references | ||||||||||||||||||||||||
| Specific Gravity | 3.05 to 3.21, Blue Chart Gem Identification (2010) More from other references | ||||||||||||||||||||||||
| Cleavage Quality | Distinct, Gemmological Tables (2004) More from other references | ||||||||||||||||||||||||
| Fracture | Uneven, Gemstones (2009) | ||||||||||||||||||||||||
| Optical Properties of Andalusite | |||||||||||||||||||||||||
| Refractive Index | 1.629 to 1.660, Gemmological Tables (2004) More from other references | ||||||||||||||||||||||||
| Optical Character | Biaxial/-, Blue Chart Gem Identification (2010) More from other references | ||||||||||||||||||||||||
| Birefringence | 0.007 to 0.013, Blue Chart Gem Identification (2010) More from other references | ||||||||||||||||||||||||
| Pleochroism | Orange/brown stones - strong trichroism: yellow - olive green - reddish brown; Yellow stones - strong: yellow - olive-green - red-brown; Green stones - strong: yellow - olive green - red-brown, Blue Chart Gem Identification (2010) More from other references | ||||||||||||||||||||||||
| Dispersion | 0.016, Gemstones (2009) | ||||||||||||||||||||||||
| Colour | |||||||||||||||||||||||||
| Colour (General) | Green, yellowish-green, brown, pink, colourless, Gemmological Tables (2004) More from other references | ||||||||||||||||||||||||
| Causes of Colour | Green and brown, pleochroism Fe2+ -O- Ti4+ charge transfer. Dark green, Mn3+ in octahedral coordination, Pragmatic Spectroscopy For Gemologists (2011) | ||||||||||||||||||||||||
| Transparency | Transparent,Translucent,Opaque, Gemmological Tables (2004) More from other references | ||||||||||||||||||||||||
| Lustre | Vitreous, Gemstones (2009) | ||||||||||||||||||||||||
| Fluorescence & other light emissions | |||||||||||||||||||||||||
| Fluorescence (Short Wave UV) | Dark green to yellowish-green, Gemmological Tables (2004) More from other references | ||||||||||||||||||||||||
| Fluorescence (X-RAY) | The brownish greenstones from Brazil often show greenish yellow under X-rays., Gems, Sixth edition (2006) | ||||||||||||||||||||||||
| Crystallography of Andalusite | |||||||||||||||||||||||||
| Crystal System | Orthorhombic, Blue Chart Gem Identification (2010) More from other references | ||||||||||||||||||||||||
| Habit | Prismatic habit with vertically striated prisms which are nearly square in section and capped with pyramids, Gems, Sixth edition (2006) More from other references | ||||||||||||||||||||||||
| Inclusions in Andalusite | |||||||||||||||||||||||||
| Rutile needles - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 4 Needle-like crystals, liquid inclusions - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 16 | |||||||||||||||||||||||||
| Further Information | |||||||||||||||||||||||||
| Mineral information: | Andalusite information at mindat.org | ||||||||||||||||||||||||
| Significant Gem Localities | |||||||||||||||||||||||||
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