Gustav Tschermak
The Vienna mineralogist who named maskelynite, the shocked glass in the Shergotty meteorite, and helped classify meteorites.
Key facts
- Born
- 1836
- Died
- 1927
- Nationality
- Austrian
- Field
- Mineralogist
Gustav Tschermak, later Tschermak von Seysenegg, was one of the leading mineralogists of the nineteenth century. He was curator of minerals at the imperial collection in Vienna and then professor at the university for many years, and he founded a mineralogy journal still known by his name.
Tschermak studied meteorites closely through the microscope. In 1872 he described a stone that had fallen at Shergotty in India in 1865 and found something strange: crystals with the outward shape of plagioclase feldspar but made of clear glass. He named this material maskelynite, after the British mineralogist Nevil Story-Maskelyne. Much later it was shown that maskelynite forms when feldspar is hit by a shock wave so strong that its crystal structure collapses without melting.
Shergotty itself turned out to be far more important than anyone could have guessed. In the 1980s it was shown to be a rock from Mars, and it gave its name to the shergottites, the most common Martian meteorites.
In 1883 Tschermak published a beautifully illustrated study of meteorites seen under the microscope, and he improved Gustav Rose's classification. His scheme, extended by Aristides Brezina, was used for decades. He also wrote a famous mineralogy textbook, used by students for generations.