Both halotrichite and pickeringite crystallize as post-mining formations in old galleries.
Pickeringite Mg[Al.sub.2](S[O.sub.4])[.sub.4] 22[H.sub.2]O
Pickeringite was identified by Bandy (1944) as a post-mining formation in old galleries, together with halotrichite.
Other minor associated minerals include kalinite, mirabilite, alunogen, pickeringite
Associated minerals are: melanterite, pickeringite
, potassium alum, jarosite, gypsum, arsenolite, sulphur and some unknown minerals.
Associated minerals are: coskrenite-(Ce), zugshunstite-(Ce), melanterite, halotrichite, pickeringite
, apjohnite, epsomite and other hydrated sulfates.
20Mg[A1.sub.2][([SO.sub.4]).sub.4]*22[H.sub.2]O + 50[H.sub.2]O + 4[H.sup.+] pickeringite in hair salt
Pickeringite (?) (Mg,Mn)[Al.sub.2][([SO.sub.4]).sub.4]*22[H.sub.2]O
Silky white fibrous masses of manganoan pickeringite were identified as hair salt by their appearance and astringent taste; it forms a solid solution with halotrichite and apjohnite, and is distinguishable with certainty only by analysis.
Fast-growing fibrous masses of halotrichite and pickeringite are common in many of the Cerro Rico adits and drifts.
Pickeringite Mg[Al.sub.2][([SO.sub.4]).sub.4][center dot]22[H.sub.2]O
Associations include other rare secondary sulfates, especially pickeringite
; thoughtfully, all specimens have been reinforced by spraying.