Today I went with #Vivianite over #Cavansite for #MinCup23, notably because 1) have you seen that green (next bracket might be a tough choice, as it is pitted against dioptase...) and 2) just found that it was use as a green pigment by Vermeer (thanks @minouette for the information), and that's kind of my current hyperfixation, so...

#Cavansite is also blue and contains crystal water, but it is a silicate with the chemical composition Ca[V(+IV)O|Si4O10] · 4H2O. The name comes from the calcium and vanadium cations it contains. Isn't it beautiful?

I am all about learning new things and also I have to deal with V-containing materials at work quite a lot, hence my vote goes to #Cavansite.

📷 Parent Géry

Hmmm. #vivianite vs #cavansite is not a very chaotic matchup at all - they're both very pretty and fairly rare, the latter moreso than the former, but not very chaotic.

Cavansite owes its gorgeous blue to vanadium, but it's too rare to be a common ore, so it's more usually a collector's mineral. And vanadium isn't really much fuss until you process it, as far as I can tell; just exercise a little common sense in handling, per most minerals. (c) #MinCup23