Here you will find links to sites that deal with the topic!
I´m not responsible for the content of the linked pages!
Lungauer Stoafexn - www.lungauer-stoafexn.at
Roberto Bianchi - mineralidellealpi.altervista.org
Jonas Norpoth - http://www.jnminerals.com
Webshop `We love minerals` - https://weloveminerals.com/