Steverustite is a secondary mineral of copper and lead with an interesting and rarely occuring (in nature) thiosulphate anion (S2O3) within its structure.
Named after UK mineralogist and collector Steve Rust the mineral was first discovered at the Frongoch Mine, Ceredigion in Wales in 2008.
Steverustite is a supergene mineral formed through the oxidation of combined lead and copper sulphide ores.
The discovery at Frongoch lead to investigation at similar locations in the UK and very soon a number of localities hosting steverustite were found across central Wales and at Leadhills in Scotland.
The geological context for steverustite should mean that it should occur at other places but so far the only sites are in the UK. This might be a case of people not having looked for or observed the mineral.
This remained the case for 10 years or so, until this year when Jason Smith (Bucket of Holes Minerals) made another discovery in North Carolina, USA .
During February 2018 Jason collected a number of micro specimens from a lead trial at Redmond near Waterville Lake, Hayward County and has been working to identify and catalogue a number of these.
In amongst the specimens were some samples of crystals visually similar to steverustite, and with PXRD work undertaken by Anthony Kampf the occurence was confirmed.
Steverustite - Redmond Mine, North Carolina, USA
Taken from Jason's words "Redmond Mine is a small underground lead prospect that was worked for lead and minor copper at an unknown time (to me).
We have been investigating it over the last year after seeing an ‘azurite’ specimen in an old collection that was clearly linarite. We have found quite a few species we didn’t expect, including susannite, redgillite, wroewolfeite and several others that are new for the state and for the USA.
The steverustite was analyzed by PXRD and is associated with caledonite, susannite, bechererite, anglesite and a phase that may be fassinaite.
PXRD Spectrum from Jason's Specimen
Steve Rust has found the species in numerous old lead mines in the UK but this is the first locality outside these localities and Great Britain."
Inside Redwood Mine
Maybe in due course there will further discoveries of steverustite around the globe?!