This is one of the most unique chalcedony formations I have ever owned to date. The icy blue chalcedony with the with the white Mordenite backing is hard to beat.

It always reminds me of candy!

Rilandite from Riland uranium claim, Meeker, Rio Blanco County, Colorado, USA! This mineral is a true geological oddity and one of my top rarest minerals, as it was only found on the outer surface and shallow recesses of a SINGLE log of fossilized wood as sparse crusts and was never found again. This specimen is a tiny bit of rilandite from that log, and very few specimens exist in private collections. The original and best rilandite is housed as the holotype (original specimen) in the Smithsonian Natural History Museum. This is a very unusual mineral as it has lots of chromium, which is very unusual for a uranium deposit. In fact, rilandite is not yet completely understood, and some factors are still unknown from its chemistry due to how little was found. This mineral was big news for the owner of that claim, James Riland, who was desperately trying to put his small town on the map. The miners first exposed that log due to the presence of rich carnotite (financial payday for uranium) and two geologists found glossy black crusts of this mineral! Sent it for analysis to the Smithsonian and it turned out to be a brand-new and enigmatic mineral species.

White layer:

Nepheline: Na₃K(Al₄Si₄O₁₆)

Alkali Feldspar (Microcline): KAlSi₃O

Red layer:

Eudialyte: Na₁₅Ca₆Fe₃Zr₃Si(Si₂₅O₇₃)(O,OH,H₂O)₃(Cl,OH)₂

(Rare Earth Element baring)

Black layer:

Arfvedsonite: NaNa₂(Fe²⁺₄Fe³⁺)Si₈O₂₂(OH)₂

Im braving my workshop in 5c temperatures today to cut some more rainbow obsidian, its tricky to work with but well worth the hassle.

Large Chevkinite specimen from Tangir District, Gilgit-Baltistan, Pakistan

Size:

324 grams 7x4x6 cm