#Neptunite is one of a few calcium-free titanium silicates (incl. benitoite). Seems like an obscure fact but:

#Zircon includes titanium in its structure, as a function of temperature; this can be a #geothermometer.

To standardize a microbeam analysis (like laser ablation ICPMS), we need a mineral with a known composition, lots of titanium and silica and no calcium, which has an isotope at mass 48. Neptunite and benitoite are perfect for this.

#MinCup23 #ICPMS #chemistry #geology

I’m going with #Neptunite for today’s #MinCup23 matchup. It has beautiful crystals, is friends with Benitoite, and it’s named after the Roman god of the sea because of its close association with aegerine (named after the Norse god of the sea) at its type locality.

Photo from Mindat and by Fabre Minerals (www.fabreminerals.com)

We’ve almost finished the first round! #MinCup23 R1 Match 14:

It’s the glowing party of dangerous elements #Arsenuranospathite against the dark & opaque #Neptunite. You only get one.

Vote: https://www.mineralcup.org/2023/campaigns/round-1-match-14

Results: https://www.mineralcup.org/results/round-1-match-14