• Chemistry: SiO2; Fused Silicon Dioxide.
  • Class: Mineraloids
  • Group: Some minerologists place lechatelierite in the Quartz Group.
  • Uses: Only as mineral specimens.
  • Specimens

Lechatelierite is considered a mineraloid because it lacks a crystal structure. It is actually made of fused silica; SiO2. Quartz is also made of silica, but it has a crystalline structure. Basically lechatelierite is glass! However, it differs from regular glass by virtue of its natural origins. Lechatelierite is also not the same as obsidian. Although obsidian is considered a natural glass it is not pure SiO2. And although lechatelierite is sometimes formed as a result of meteorite impacts like tektites, they are not the same. Unless the tektites are very pure silica as in the case of a variety called Libyan Glass (see above). To sum all of this up, lechatelierite is natural, pure or nearly pure, silica glass.

Lechatelierite has three different origins: Meteorite impacts, volcanism and lightning strikes. The meteorite impacts simply fused quartz grains in the impacted rocks with the incredible pressures that they generate. The volcanism origin is the same as for obsidian, where molten rock cools too quickly for a crystalline structure to form. But as was explained before, obsidian is generally a mix of several chemistries besides SiO2. The lightning strike origin is perhaps the most interesting.

When lightning strikes the earth in sandy areas such as deserts or sandy beaches, the intense heat and energy of the bolt will fuse the sand grains in a milli-second. A branching, hollow, glassy tube is sometimes the result. These "fossil" lightning strikes are composed of lechatelierite and occassionally fused biotite or other minerals. They are referred to as fulgarites and are certainly a natural history oddity. Fulgarites have been found that were several feet in length, although most are a few inches long by a half inch thick.


  • Color is white, colorless or pale yellow; some fulgarites can be pale brown, gray or black.
  • Luster is vitreous.
  • Transparency: Specimens are translucent.
  • Crystal System: Does not apply because lechatelierite is amorphous.
  • Habits include disseminated grains in volcanic rocks and shatter zones of meteorite impacts and as tube shaped fulgarites (see above).
  • Cleavage is absent.
  • Fracture is conchoidal.
  • Hardness is 6.5
  • Specific Gravity is approximately 2.5 - 2.7 (average)
  • Streak is white.
  • Other Characteristics: Non-fluorescent.
  • Associated rocks are shocked quartz, volcanic rocks and sandy soils.
  • Best Field Indicators are shape, color, density, non-fluorescence and hardness.
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LECHATELIERITE specimen lec-1
$ 30.00
Dims: 3.09x0.59x0.43" (7.84x1.49x1.10cm)
Wt: 0.14oz (4.0g)
Al Kufra, Libia
This is a fulgarite, an example of sand fused into a glass by lightning. Generally found in deserts, they are formed when a lightning bolt strikes the top of a sand dune, and the intense heat causes the sand to melt and fuse into an amorphous glass along the path of the lighting. Of course, the bolt quickly spreads into smaller and smaller branches, yielding a kind of fossil imprint of the lighting strike. The main strike can be many centimeters wide and meters long, but most fulgarites are a centimeter or two in diameter, and no more than tens of centimeters in length. This one is a very light-weight thin hollow tube, coated with the light-brown sand from which it formed.
no photo
lec-1 ($ 30.00)
Al Kufra, Libia
LECHATELIERITE specimen lec-2
$ 28.00
Dims: 3.16x0.55x0.47" (8.02x1.41x1.21cm)
Wt: 11.5ct (2.3g)
Al Kufra, Libia
This lechatelierite specimen is a fulgarite, the result of a lighting strike in desert sands. It is an extremely light and very thin shell, with many tiny holes. The color varies from light brown to nearly white, with many tiny black specks. A loupe reveals that the interior is smooth and glassy, while the outside is rough, as these crystals of sand were only partially melted and are welded in to the lechatelierite tube.
no photo
lec-2 ($ 28.00)
Al Kufra, Libia
LECHATELIERITE specimen lec-3
$ 25.00
Dims: 2.47x0.65x0.41" (6.29x1.64x1.05cm)
Wt: 0.13oz (3.6g)
Al Kufra, Libia
This specimen of lechatelierite was formed as a fulgarite, the result of a lightning strike in desert sands. It is amazingly light, which is due to its nature - a hollow tube of fused quartz. The interior was, of course, vaporized, and the lechatelierite is the fused, glassy material lining this cavity. On the outside, there are partially melted grains of sand fused into the shell, so it has a much rougher appearance. On the ends of the tube, a loupe reveals the transitions between the lechateliearite and the original quartz.
no photo
lec-3 ($ 25.00)
Al Kufra, Libia
LECHATELIERITE specimen lec-4
$ 45.00
Dims: 6.12x0.54x0.35" (15.54x1.36x0.88cm)
Wt: 0.38oz (10.7g)
Al Kufra, Libia
This is a collapsed fulgarite. a fossil lightning strike that collapsed from a hollow tube of molten glass (lechatelierite) to a flattened tube before it cooled. A loupe is needed to examine the glassy (and transparent) lechatelierite, exposed at the edges of the specimen. Most of the specimen's appearance is due to the bits of sand and soil frozen into the surface of the lechatelierite as it cooled, giving it a gray appearance due to black, white, and gray components.
no photo
lec-4 ($ 45.00)
Al Kufra, Libia
LECHATELIERITE specimen lec-5
$ 30.00
Dims: 2.14x1.16x1.01" (5.44x2.96x2.56cm)
Wt: 0.78oz (22.0g)
Al Kufra, Libia
This is another fulgarite, a fossilized lightning strike composed of sand grains fused into the glass lechatelierite around the hollow excavated by the lightning bolt. It is relatively thick and heavy for a fulgarite, and is a dark gray in color with little white grains of sand speckling the surface.
no photo
lec-5 ($ 30.00)
Al Kufra, Libia


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