Congratulations to our Mineral Cup 2026 Champion Quartz! For #MinCup26, we collectively chose a nostalgic beauty of resilience as persistence as our champion. Please celebrate #Quartz, a friend to humans since time immemorial! www.mineralcup.org/about/2026-q...

Subducted chert with perfect little #garnets scattered in a sea of #quartz, as seen under cross polarized and plane polarized light; FOV ~ 1.5 mm. Laytonville, California US. Garnet has previously won #MineralCup and maybe 2026 is finally the year for #quartz! #MinCup26

A 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 🍎 🪐 🔭 🌋 📚 🌿

Andalusite gets arts points as gem & physics points for pleochroism & as index mineral. But Cuprite wins art vote as a red pigment in glass, enamels, bronze patinas & ceramics. Colours range from blood red to purple/brown in a reducing atmosphere & change to green in an oxidizing kiln. #MinCup26

Mineral Cup & Ore Cup@mineralcup.bsky.social · last mo.

#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...

One 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

If 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

“In thin section (a slice of rock about 30 µm or 0.03 mm thick) (andalusite) chiastolite makes beautiful images. The textbook-quality photo above is by Chris Gammons of a specimen collected by Joel Dietrich in the Flint Creek Range of southwest Montana” From @richardgibson.substack.com Link in ALT!

Beautiful #andlausite with a crystallographically-controlled cross of #graphite inclusions (chiastolite). It would be epic to have an andalusite vs graphite match, if only andalusite can prevail over cuprite. #MinCup26 #MineralCup

The dark mineral in these plane (L) and crossed polarized (R) light photos of a subducted metasediment from Corsica is mostly #graphite. Some occurs as inclusions in #lawsonite, defining micro-folds. #MinCup26, #MineralCup

#Riebeckite occurs in some alkali granites and banded iron formations and it can occur in blueschist. It is more iron-rich (including Fe3+) than the more famous #glaucophane. This photo shows a sodic amphibole zoned from Mg-rich core to iron-rich rim in chert that was subducted. FOV 2 mm. #mincup26

Pink #andalusite intergrown with blue #kyanite — which came first? #Mincup26 #mineralcup

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Source: Frontiers for Young Minds

International Women’s Day march in Berlin

Epic #kyanite crystals reveal their colors when split open. We are tracking variation in extent of kyanite to sillimanite transformation in a metamorphic dome — it varies from 0-100% with structural location in the dome: one of the many geo-useful and fun things you can do with kyanite. #MinCup25

These white #kyanite crystals in a biotite-gedrite schist from central Australia somehow missed out on the titanium, iron, and other trace elements that kyanite typically contains to give it the iconic blue and other colors. #MinCup25

This rock in western Norway originated as basalt in an ancient ocean, then it was buried (subducted) tens of kilometers and heated over 800 C to create this beautiful #kyanite. The alignment of the kyanite indicates deformation. #MinCup25

Chromium-rich #kyanite blood, as seen with cathodoluminescence imaging. #MinCup25

#kyanite party (Roan, Norway) #MinCup25

I’m very excited that #tugtupite made it to the finals but can it do this? Folded #kyanite in a high-pressure quartzite, western Türkiye. #MinCup25

Hematite is red, #kyanite is blue, And also green, white, black, and orange too #MinCup25

#kyanite (blue) replacing or being replaced by pink #andalusite. Bonus: there is also #sillimanite, so this a rare locality containing 3 Al2SiO5 minerals (polymorphs). Lesjaverk, Norway. #MinCup25

#kyanite wave (Western Gneiss Region, Norway) #MinCup25

NOTE: MSA Inaugural Annual Meeting: Feb, 16-18, 2026, Tucson, AZ, USA This will follow the Tucson Gem and Mineral Show. On Feb. 17 and 18 there will be a series of talks and poster sessions. Abstracts due: Oct. 31. Registration will be through the MSA website at www.msaweb.org

#kyanite fields forever, or until the next orogeny #MinCup25

#kyanite in biotite gneiss from the Entia Dome, central Australia. Kyanite forms deep in the crust before it makes its way to the Earth’s surface, a slow and much more challenging journey than taenite’s fall through space. #MinCup25

#kyanite volcano (not really a thing but a nice way to display the different colors of kyanite) #MinCup25

#Garnet swimming in a sea of #Titanite in a Franciscan Complex metamorphic rock, as seen in plane and cross polarized light. Photo by Sarah Brandt. #MinCup25

#Titanite from the Franciscan subduction complex, California, as seen under plane and cross polarized light in a petrographic microscope. Field of view about 2 mm. Photo by Sarah Brandt. #MinCup25

Magnetic and Crystallographic Fabric Analyses of Amphibolite: A Proposed Methodology Applied to a Migmatite Dome - Hamelin - 2025 - Journal of Geophysical Research: Solid Earth - Wiley Online Library agupubs.onlinelibrary.wiley.com/doi/10.1029/...

Magnetic and Crystallographic Fabric Analyses of Amphibolite: A Proposed Methodology Applied to a Migmatite Dome

Anisotropy of Magnetic Susceptibility provides an efficient, first-order characterization of amphibole-dominated rock fabrics Rapid, simple methods open applications to structural field studies i...

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