Tiny white microcrystals of torrecillasite - a brand new mineral species from Chile.

Abstract from the first publication:

"Torrecillasite occurs as a secondary alteration phase associated
with anhydrite, cinnabar, gypsum, halite, lavendulan, magnesiokoritnigite, marcasite, quartz, pyrite, scorodite, wendwilsonite, leverettite, canutite, and several other potentially new arsenate and arsenite minerals.
The mineral is assumed to have formed from the oxidation of native As and other As-bearing primary phases, followed by later alteration by saline fluids derived from evaporating meteoric water under hyperarid conditions.
Torrecillasite occurs as thin prisms up to 0.4 mm long in jackstraw aggregates, as very thin fibers in puff balls, and as massive intergrowths of needles. Prisms are elongated on [100] with diamond-shaped cross section and have irregular terminations. Crystals are colorless with a white streak, adamantine, with no cleavage, have an irregular fracture, brittle tenacity and a Mohs hardness of 2½ "
(A.R. Kampf et al (2014) Torrecillasite, Na(As,Sb)4
3+O6Cl, a new mineral from the Torrecillas mine, Iquique Province, Chile: description and crystal structure. Mineralogical Magazine, 78(3), 747–755.)

SEM/EDS conformed specimen.