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/