@silicatefondue @rpmik Oh hello now! This alone justifies my vote for #Leucite in today’s Mineral Cup 2025 contest! I’m a longtime victim or benefactee of Leucite most likely.

#Leucite is used to make dental porcelain (or rather, leucite + glass from melting feldspar incongruently). Thiis is becuase it:
is immune system compatible
is machinable
is fracture resistant with low porosity
it doesn't easily stain or discolour
and most importantly, its thermal expansion matches the metal anchor

Image from: J.R. Mackert et al (1986)The effect of the leucite transformation on dental porcelain expansion, Dental Materials 2: 32-36

#MinCup25 #Dentalimplant #Ceramic

Oh noooooo, I think people are voting for the pretty fluorescent view of the cobalt glow from the first specimen in the page! Clearly my choice is heavily out-voted at present! C’mon my rock people homies, help me out with your vote on the Leucite. And do look at the hashtags where you’ll find the Mastodon fans providing fascinating information. #Carpathite #Leucite

Ok I am now changing my intended vote to Leucite after reading the history and geology from the pages links by contributions in posts. I’m telling you, you are missing out if you don’t click on the hashtags and travel deeper. Although my artist eyes were immediately drawn to the cobalt blue glowing, the Leucite Hills in Wyoming have history back to 1871 explorations and the lamproites glinting with tiny Leucite crystals sparked further research. #Carpathite #Leucite #MinCup25

@silicatefondue oh my new strange lands and ideas are now available to me. The page linking to the Wyoming Leucite Hills is a goldmine of geological information and discoveries.

Even more entrancing to my artist eyes, the landscape photography shown is from the Tumbler for mypubliclands. I think this means it was from BLM photographers and I wonder if this deep knowledge has been protected from disappearing online and that the BLM scientists and photographers are still employed, considering US administration changes.

If I was able to do so, I’d order prints to frame from the landscape photography here. A perfect area for drone photography if you can’t fly over the vast expanses. #Leucite #MinCup25

@silicatefondue Oh my the thin section slide photos are fascinating to see the amazing transitions for crystals in high heat! Thanks for sharing the Smith College page! “Strange, high potassium lamproites” - what a phrase. I have no idea what that means but now must have a look. Appreciate very much your information on #MinCup25 for #Leucite and #Carpathite

I have never heard of either mineral and that’s a bit rare for me, but then if I were a chemist I might have. The vote today is for Carpathite and Leucite. Anyone here in Mastodon know about either? This is a screenshot of the page to vote. Anyone can vote and no need to register. I bet there will be fewer than the usual 1,000 votes. Link below

Of course I am drawn to the first, #Carpathite because it is shown in typical light as green and then fluorescent as very glowing blue. Like a cobalt blue from the unknown dark matrix rock and vivid light blue from the green star shape of needle-type crystals. #Leucite looks terrible on the page as a cloudy dull crystal nicknamed a white garnet.

https://www.mineralcup.org/2025/vote/r1m06

@FaithfullJohn Unfortunately it suffers from negative relief and pitiful birefringence so it has an image problem...

#MinCup25 #Leucite

Leucite has a range of volcanic hills named after it, see:
https://www.geowyo.com/leucite-hills.html

These are strange, high potassium lamproites from the mantle, only 1-2 million years old.

Match that, organic goo #carpathite !

Students at Smith College have a nice page of #leucite thin section images:
https://www.science.smith.edu/geosciences/petrology/petrography/leucite/leucite.html

#MinCup25 #SmithCollege #Wyoming #Lamproite #OrganicGoo

#MinCup25 Today is #leucite vs #carpathite. Leucite is nice - readily forms lovely 24-faced icosatetrahedral crystals looking like white garnets. And only found in insanely K-rich and Si-poor igneous rocks - eg Vesuvius. However, it's got to be carpathite for me. A rare + astounding crystalline organic material formed from hot waters. It forms lovely crystals, has a sparkly high refractive index + fluoresces fabulously under UV light. A miracle of nature! #Geology #Mineralogy #Coronene

#MinCup25 Round 1 Match 6: Brace for oddness in a match between one of the very few hydrocarbon minerals #carpathite and the temperature-flipping mineral #leucite.

Vote: https://www.mineralcup.org/2025/vote/r1m06
Results: https://www.mineralcup.org/2025/results/r1m06

@MineralCup Actually I am looking forward to Match 6 with Carpathite (3c) (a.k.a Coronene) against Leucite(3d). It will be good to have a nice organic compound to play with when you follow the link:

https://cds.dl.ac.uk/cgi-bin/rfm/crystalworks_trawl_new?8850_3368_5146

It is now time to vote!

Fun fact you can get a different polymorph of synthetic Coronene if you crystallize it in a strong magnetic field

#MinCup25 #Carpathite #Coronene #Leucite