Prehnite

Very common mineral from the "silicates and germanates“ class.

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Prehnite from India

Origin of name: named after Dutch Baron and Colonel Hendrik van Prehn (1733–1785),  from 1768 commander of the military forces of the Dutch colony at the Cape of Good Hope and governor from 1779 to 1780. He also was an ardent mineral collector and brought the first specimens of his namesake mineral to Europe. In 1788 Abraham Gottlob Werner, one of the most distinguished mineralogists and geologists of his time, recognized the samples as a new mineral and called it in honour of its finder.

Synonyms and trade names: Cape Chrysolite, Cape Emerald

Can be confused with: several other gem stones of similar colour e.g. chrysoprase, peridot, beryl, tourmaline, hiddenite, jade, brazilianite and others

Localities: at the time of writing (2024) mindat.org lists more than 2400 localities.
Type locality is the dolerit deposit at Karoo, near Cradock, Eastern Cape, South Africa.
Other noteworthy localities are Australia, Mali, India and the USA.
In Austria more than 100 deposits are known.

Fine translucent prehnite from Australia

Handling: prehnite is rather insensitive towards acids but it is pronouncedly heat-sensitive. Keep away from blow-pipe, ultrasonic cleaners and galvanic baths!

Worth knowing: allegedly prehnite was the first mineral named after a man

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