@sorosilicate.bsky.socialOne day during field work in Türkiye, I sat in a dry stream bed to eat lunch and found this #andalusite + quartz rock next to my foot! I walked upstream until I found the outcrops, and ended up with an unexpected new research project on this surprising rock! #MinCup26 #MineralCup
@sorosilicate.bsky.socialIf you (or the Earth) heats up #kyanite at low pressure (shallow depths), you get #andalusite! Both are Al2SiO5, but with distinct crystal structures. #MinCup26 #MineralCup
@tanterei.bsky.social@mineralcup.bsky.social
For this round this picture looks like a big rock of #Andalusite in the light!
It's interesting how both #kyanite and #andalusite are neighbours on the phase diagram and look quite different - colour-wise!
@cosmicyote.bsky.socialVote for #Andalusite because of its variant form Chiastolite! It forms a cross shape crystal with the black being carbon inclusions. It is such a neat looking rock!
@mexporg.bsky.social#Andalusite belongs to important petrology minerals and forms interesting crystal growths and pseudomorphs.
Learn more in our detailed overview:
@microtopico.bsky.socialToday, for me it's the index mineral and sibling to #Kyanite: #Andalusite!
@ougeolsoc.bsky.socialBeautiful in gem-like versions, but the fun of climbing up onto Dartmoor, finding spotted slate with chiastolite/andalusite porphyroblasts before getting to granite, and spotting a tiny, perfect cross in the "spot"!
Vote #andalusite #MinCup2026
www.alexstrekeisen.it/english/meta...
@vickyveritas.bsky.socialA small but beautiful gem quality golden terminated #andalusite that deserves your vote. Today I am voting for a mineral that didn’t get eliminated (unlike yesterday, DOH!) Progress 😆
#MinCup26 ⚒️ sci-fi 🧪 🖖🏼 scifi Geosciences #WomenInSTEM geology #geosky #GIS 🍎 🪐 🔭 🌋 📚 🌿
@warriorchicken.mePleochroism with bonus points as an index mineral. #Andalusite had my vote in round 1 and retains it in round 2
@louisedawe.bsky.socialVoting #Andalusite for #MinCup26! In @actacrystb.iucr.org, Pilati et al. use a lattice-dynamical model to predict its atoms’ thermal motion, specific heat and entropy, in close agreement with experiment. Structure is not just a still image. Read more: journals.iucr.org/paper?cr0515=
@crystallised-cricket.comI'm still salty that #Cupirte beat #Orpiment in the first round of #MinCup26 - so today's vote is for #Andalusite out of spite. Plus it has got a more interesting crystal structure, so there's that too.
@mineralcup.bsky.social#MinCup26 Round 2 Match 3:
It's a shiny showdown as soft copper-rich #Cuprite is up against the multicoloured index mineral #Andalusite.
VOTE: www.mineralcup.org/2026/vote-re...
RESULTS: www.mineralcup.org/2026/vote-re...
@silicatefondue.fosstodon.org.ap.brid.gyGraphite inclusion trails link the corners to the centre of this andalusite crystal. From an unknown locality, in our teaching collection.
#MinCup26 #Graphite #Andalusite
@daverodland.bsky.socialFor #MineralMonday we have the aluminosilicates ... kyanite won last year, but #andalusite is in the mix for #MinCup26!
No pressure.
@cosmicyote.bsky.socialVote for #Andalusite #MinCup26
Cool rock plus kinda funny story for how it got it's name
@bkania.bsky.socialGreat photo of #Andalusite
@clairecopperman.bsky.socialI hadn't heard of either mineral today, but looking at the QPs and the photos, #Andalusite gets my vote, if only because it's pleochroic - a new word for me, and seriously cool.
#MinCup26
@silicatefondue.fosstodon.org.ap.brid.gyAndalusite thin section in cross-polarized light. Faint chiastolitic (is that an adjective?) inclusion trails link the corners of the crystal. From an unknown locality, in our teaching collection.
