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@mineralcup.bsky.social Sep 29, 2026, 1:12 AM

#MinCup26 SEMI-FINALS!!!

It's showdown of the soft and cubical as coppery #Cuprite and salty #Halite compete for a spot in the finals! Both are worthy, but only one can have your vote.

VOTE: www.mineralcup.org/2026/vote-re...
RESULTS: www.mineralcup.org/2026/vote-re...

Split photo of a translucent deep red cube of cuprite within swooping matte blue-green crystal blades and a scattering of translucent white halite cubes in a nest of golden yellow spiky crystals.

@bowtiediene.bsky.social Sep 29, 2026, 12:08 AM

#MinCup26 You seem like the brilliant sort, so vote for the mineral with greater brilliance than diamond. #Cuprite

@bowtiediene.bsky.social Sep 25, 2026, 11:20 PM

#MinCup26 #Cuprite can form a d6, d8, d12 dice shape! Vote for that wonderful overlap between geology and #TTRPGs!

@bkania.bsky.social Sep 25, 2026, 8:04 PM

So does #FossilFriday have any #Thoughts or musings for the #MinCup26 #QuarterQuells match up between #Sphalerite & #Cuprite hmmmm❓️inquiring minds do wish to know. @mineralcup.bsky.social

@tanterei.bsky.social Sep 25, 2026, 7:03 PM

This time I have to give Sphalerite up. It's #Cuprite for me in the QF!

Just consider that this red gem can coexist with malachite in a single node!

Really wish I could find a more impressive picture for #MineralCup26 😔

A crystal of malachite with cuprite regions. Source : https://de.wikipedia.org/wiki/Cuprit

@clairecopperman.bsky.social Sep 25, 2026, 5:52 PM

This could be the closest round yet in #MinCup26: atm there's just one vote in it. I'm Team #Cuprite for its use in art and for introducing me to the word pleochroic - changing colour depending on the angle. Besides, do you really want #Sphalerite's smell of rotten eggs?

@ougeolsoc.bsky.social Sep 25, 2026, 1:07 PM

Got me looking in various directions as I hadn't come across "ruby copper" aka #cuprite despite living in and around Cornwall... copper mine country... for half my life! Knew copper weathered to gossan/iron hat but cuprite was new to me and believe I have some somewhere :) vote #cuprite #MinCup26

@vickyveritas.bsky.social Sep 25, 2026, 12:25 PM

This was a tough decision! I love the triangular facets/chip on both samples (look close!), but ultimately I love the cubic #Cuprite which reminds me of my favorite mineral.

#MinCup26 ⚒️ sci-fi 🧪 🖖🏼 scifi Geosciences #WomenInSTEM geology #geosky #GIS 🍎 🪐 🔭 🌋 📚 🌿

@wonderbooze.bsky.social Sep 25, 2026, 3:45 AM

Battle of the Shiny Rocks part deux! Team #Cuprite

@crystallised-cricket.com Sep 25, 2026, 12:10 AM

So we enter the Quarter Finals of #MinCup26 - and first up is semi-boring structure #Sphalerite vs boring structure #Cuprite. Maybe it's just because it's my last day before leave, but can't seem to care about either of them... I guess as a neutron scatterer I'll have to go for magnetic #Cuprite

Image of the crystal structure of Sphalerite - here yellow sphere represent sulfur atoms and grey spheres/polygons represent zinc. The structure is viewed off the principle axes so that the repeats can be seen and is drawn in VESTA from #110 in the American mineralogist database

Image representing the crystal structure of Cuprite - here red spheres represent oxygen atoms, and blue spheres represent copper atoms. The structure has been expanded over a,b and c axes to show off quite how boring it actually is. Just copper bonding to oxygen, not even making up a polygon. Literally without the magnetic properties of this mineral has it would be a right snooze-fest. The representation is drawn in VESTA from entry #7351 in the American mineral database