Tektite

Big Photo

Moldavite
Czech Republic
9.63 carats
© irocks.com

Tektite is a natural glass formed from a meteorite impact melting the local rock.

Many varietal names are given to Tektites from different localities.

Moldavites are oval or spherical specimens of pale or bottle-green colour with few included bubbles and less obviously flattened from the Radomilice area of southern Bohemia, Czech Republic.

Bikolite is a name given to Tektites from the Bikol area of the Philippines.

Australites are button-shaped glass pieces found in South Australia and Tasmania. Billitonites are dark brown specimens found on Billiton Island between Sumatra and Borneo.

Darwinites or Queenstownites are silica-rich and alumina-poor colourless to olive green to black specimens from Jukes-Darwin field near Queenstown, Tasmania.

Tektites can be distinguished from the much more abundant volcanic glasses (obsidian) by their negligible water content. A small splinter of tektite will fuse quietly in a flame to a droplet of glass, whereas a splinter of obsidian will froth up and expand in a flame owing to its small water content turning into steam.

Tektite Gemstones by Colour

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

Tektite Gemstones by Size

This table shows distribution of Tektite 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:1.28 cts
Heaviest:14.01 cts
Average:7.28 cts
Total photos:12
Do you have a larger Tektite? Why not upload a photo?
1.28ct to 2.55ct2.55ct to 3.83ct3.83ct to 5.10ct5.10ct to 6.37ct6.37ct to 7.65ct7.65ct to 8.92ct8.92ct to 10.19ct10.19ct to 11.46ct11.46ct to 12.74ct12.74ct to 14.01ct
General Information
Varieties/Types:
Australite - Button-shaped Tektites from South Australia and Tasmania
Bikolite - Tektites from the Bikol area of the Philippines.
Billitonite - Tektites from Billiton Island, between Sumatra and Borneo.
Darwin Glass - Silica-rich / Alumina-poor glass from near Queenstown, Tasmania
Moldavite - A green variety of Tektite from Czech Republic.
Photos of natural/un-cut material from mindat.org
Physical Properties of Tektite
Mohs Hardness5.5 to 0
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Specific Gravity2.34 to 2.51
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical Properties of Tektite
Refractive Index1.490 to 1.520
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Colour
Colour (General)Green
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Causes of ColourYellowish green, Fe2+ in octahedral coordination. Brown Fe3+ in octahedral coordination
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
Crystallography of Tektite
Crystal SystemAmorphous
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Inclusions in Tektite
Spherical or elongated (torpedo shaped) gas bubbles, swirl striae (snake-like pattern) - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 8
Further Information
Mineral information:Tektite information at mindat.org
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