Geyserite
Red and yellow crusts collected in the Valley of the
Geysirs.
For now I just call it 'Geyserite'. Note that in countless other hotsprings
around Kamchatka the red color is caused by dispersed cinnabar or realgar
and the yellow color is often caused by orpiment. I have no proof this is the
case here.
[photo/collection: Maurice de Graaf]