#cordierite

[dozydawn]

[talos-stims]

tanzanian iolite | source

[thatpollguy]

can you do a poll of this rabbit pls

Sure thing, @readilyradiantkatron of course I can! Keep the requests coming, folks 😎🧡

Do you like the character Io from the Japanese franchise "Jewelpet"?

I love him

I like him

I dislike him

I hate him

I don't know who he is

Voting ended onNov 16, 2025

[letstalkrocks]

Today's Specimen: Iolite

Iolite is a gemstone derived from the mineral cordierite. Iolite can be found in violet-blue, slightly yellow, grey, or colourless, with violet-blue being the most sought after. Iolite can be used in kiln manufacturing, since it has a very high heat resistance, as well as being used for catalytic converters in the automotive industry. Iolite is often used as a sapphire-alternative for jewelry, as it is much cheaper and easier to find. Iolite can be found across the world, including India, Brazil, Sri Lanka, Germany, Tanzania, USA, Canada, Myanmar, Australia, Madagascar, Norway, Greenland, and even Antarctica. Iolite is one of the few minerals to be mined in Antarctica. Iolite is ranked at about a 7.0-7.5 on the Mohs hardness scale. Alternate names for iolite include: Water Sapphire, Viking's Compass, Cordierite, Dichroite, Steinheilite, and Praseolite.

Stay tuned for another rock talk!

[materialsscienceandengineering]

Study reveals secrets behind cordierite's anomalous thermal expansion

Cordierite, a remarkable mineral familiar to many as the material behind heat-resistant pizza stones, exhibits an unusual ability to resist changes in size despite significant temperature fluctuations. While widely used in diverse applications, from automotive catalytic converters to high-temperature industrial processes, the fundamental reasons behind this anomalous thermal behavior have remained largely unexplained. A study, led by researchers at Queen Mary University of London and published in Matter, now provides the first comprehensive explanation, with profound implications for the design and development of advanced materials. "Modern society demands materials that exhibit minimal dimensional changes with temperature fluctuations, unlike most materials that expand and contract significantly," explained Professor Martin Dove, lead researcher and Professor of Condensed Matter and Materials at Queen Mary University of London.

Read more.

[thecapturedspy]

Junicorn Day 16: Cordierite

[earthstory]

Cherry Blossom Stones These lovely stones are found in a few rare areas in Japan, leading to their nickname as “Cherry Blossom Stones” after the famous Japanese Cherry-Blossom Trees.

They have a complicated origin. These rocks started out as shales – sedimentary rocks, probably deposited on the floor of an ancient ocean. As Japan grew, those shales were compressed and heated near magma chambers from the Japanese volcanic arc. That heat caused two chemical types of the mineral cordierite to form – the first crystal of cordierite formed and then 6 different cordierite crystals grew, radiating around the core. After those minerals formed, the rock sat there for a while and cooled off, but it was later reheated by another magmatic system. This time, the magma didn’t just add heat, it also added water from magmatic, hydrothermal fluids. Those fluids reacted with the cordierite and converted it into muscovite – a much shinier, if more friable, mineral. These rocks break easily but as you can tell they’re both fairly nice collectors items and quite rare due to the complicated sequence required to form them. -JBB Image credit: James St. John https://flic.kr/p/p1idTH Read more: http://www.mindat.org/min-1128.html https://www.wordnik.com/words/subhexagonal http://bit.ly/1LMffEU

[magnusfluorapatite]

Cordierite