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Mineral Monday: The Alfie Norville Gem and Mineral Museum of Tucson Arizona The Alfie Norville Museum (gemandmineralmuseum.arizona.edu), is housed in the Pima County Courthouse in Tucson AZ. By Andrea Koziol. #MSACommunications #MineralMonday #calcite #amethyst #geode #mineralmuseum

First heart shape I saw down at the Tucson shows, and it is a slice from a giant geode, not even amethyst crystals. This was outside lining the gallery at Mineral City. Large enough and heavy enough it needed an ironwork stand. It was raised up to eye level. Last geode post on “theme” for today. ❤️
#Heart #ValentinesDay #Crystals #Tucson #Specimen #Geode #Quartz #Chalcedony #Calcite #Slab

Pale pink slab cut from a geode with an interior mostly solid but leaving a heart shape empty. Enlarge to see details of some clear and milky color quartz crystals outlining the edge of the slab in a tall 40” triangular oval, wider across the top. Some of the slab is more translucent to let the sunlight glow through the sculpture. It has small areas staining or tint of deep red here and there. The interior agatized mass of the large geode leaves a quirky heart shape space in the center. Gray cement block wall behind slab, sunny daylight reflects from the lower wall and some shadows fill upper section of wall.

Last geode post on “theme” for today coming up… #Heart #ValentinesDay #Crystals #Tucson #Specimen #Geode #Amethyst #Calcite

Here’s another #Heart geode, this one a type of classic geode where the interior space is filled with crystals AND there is a delightful added mineral crystal form to these amethyst geodes, often calcite. This piece was likely pricy and on the top shelf. The lighting made it very attractive. Only one more #ValentinesDay geode to share and that will be later. It’s NOT amethyst! #Crystals #Tucson #Specimen #Geode #Amethyst #Calcite

Half of a geode sliced and prepared very carefully to not dislodge the pale yellow calcite cluster of large crystals. The entire specimen is about 22” wide and the calcite is about 4” across with 8 petals as it looks like a flower cluster to me. The main crystals are reddish purple amethyst with some near the op more deep purple.

I've never visited St Nectaire, in the Auvergne, Fance, but it needs to be on my list. One of the fastest depositing petrifying places on Earth I think. They've also been using this wonderful natural process to make strange artworks since the C18th. 😊 🤓

The brilliant contemporary American-Scottish artist Ilana Halperin worked with them and made some amazing pieces...

https://www.studiointernational.com/index.php/ilana-halperin-interview-geological-phenomena-volcanoes-drawing-photography-gallstones

https://www.auvergnevolcansancy.com/en/site-culturel/fontaines-petrifiantes-de-saint-nectaire/

#Petrified #Calcite #Geology #HardWater #IlanaHalperin

Screenshot of an image of an artwork by the American-Scottish artist Ilana Halperin, made using natural cave precipitation of calcite onto a mould. The work consists of crystal-like forms, on a flat smooth surface, all made of smooth clean cream-coloured material.

Rock-forming minerals

Common minerals combine to make rocks

The Earth's crust is made of over 2,000 minerals. Of these, the most abundant are feldspar, quartz, #calcite, dolomite, mica, pyroxene, #amphibole, garnet and olivine. Because they combine to make rocks, these are called 'rock-forming minerals.

Feldspars are the most abundant minerals in the Earth's crust.

Rock-forming minerals

Common minerals combine to make rocks

The Earth's crust is made of over 2,000 minerals. Of these, the most abundant are feldspar, quartz, #calcite, dolomite, mica, pyroxene, #amphibole, garnet and olivine. Because they combine to make rocks, these are called 'rock-forming minerals.

Feldspars are the most abundant minerals in the Earth's crust.

#Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines

Sometimes, Open Source developers just make me laugh and facepalm at the same time. I was looking at the docs for Apache Calcite adapters and for some reason there is an adapter which lets you query your data in *PIG LATIN*?!?! #OpenSource #Calcite #ApacheCalcite #FOSS

A screenshort of the list of adapters for Apache Calcite which shows there is an adapter which provides Pig Latin support for the query language.

Huanglong (Yellow Dragon), #China! 🐉 This #nationalpark is known for its #colorful travertine pools (saw so many walking down the #mountain!) formed by #calcite deposits, as well as diverse #forest ecosystems, snow-capped peaks, waterfalls, and hot springs, and was also declared a World Heritage Site by #UNESCO.

At an altitude of 3,552-3,576 m (my face has been tingling—had no idea that was a symptom of altitude sickness ‘til now), this is the Multi-Colored #Pool,

#Nature #Water #Travel #Photo

iPhone 12 Pro photo by Chicago artist of the Multi-Colored Pool at Huanglong (Yellow Dragon) national park in Sichuan province, China

#Greenland's #caves preserve an ancient #climate archive https://phys.org/news/2025-10-greenland-caves-ancient-climate-archive.html

"Gina Moseley and her team traveled to one of the most remote regions on Earth—Greenland's far northern coast. The Cove Cave can only be reached by small aircraft and hiking. During the expedition, the researchers discovered #calcite deposits that can form only when the ground is unfrozen and water is flowing. They show that northern Greenland was once free of #permafrost and much wetter than it is today."

photo of 2 researches in a partially rocky, partially icy cave

17-Oct-2025
Drip by drip: The hidden blueprint for #stalagmite growth
stalagmites grow into flat-topped pedestals, classical columns, or pointed cones not by chance, but according to a single controlling factor – the Damköhler number – which represents a balance between the rates of #calcite precipitation and the flow of water

https://www.eurekalert.org/news-releases/1102389

#science #geology

Gli eterei e zannuti guardiani dei branchi, che nascono grigi, poi diventano bianchi
https://www.jacoporanieri.com/blog/?p=43165

#animali #parchi #africa #namibia #elefanti #mammiferi #polvere #minerali #paesaggio #circostanze #strano #visioni #notte #sole #comportamento #creature #natura #biologia #ecologia #calcite #argilla #terra #sostrato #branchi

Gorgeous #Calcite with #Fluorite and #Quartz From Yaogangxian Mine, Hunan Province, #China..(HWD): 7 X 5 X 3.5 cm

Photo Copyright ©️ Fabian Wildfang
By #GeologyWonders
#Geology #GeologyPage #Nature #Minerals #Crystals #Gems #Nature #NatureLovers #NaturePhotography #Photographer #RockPorn

#Fluorite with #Calcite from Cave-in-Rock, Hardin County, llinois, #USA.
S:55x87х66тт

Photo Copyright ©️ peanuts_minerals
By #GeologyWonders
#Geology #GeologyPage #Nature #Minerals #Crystals #Gems #Nature #NatureLovers #NaturePhotography #Photographer #RockPorn

Look at this #calcite crystal and its super strong birefringence, yielding two distinct optical paths! And yes, that's Captain Haddock, a subtle reference to the strong polarization effects in calcite sunstones, likely used as navigational aid by seafarers in the Viking Age. #MinCup25 #teamcalcite
Vote here (only a few hours left!):

https://www.mineralcup.org/2025/vote/r1m04

Calcite crystal on top of a cartoon image of a Tintin comic album, showing Captain Haddock. The text underneath the calcite crystal appears "doubled".

Calcite vs Perovskite (planetary science edition)

Most carbonates on Mars are Fe and Mg-rich (so siderite-dolomite) but the infamous meteorite Allan Hills 84001 also containts some rare calcite.

(Mg, Fe)SiO3 perovskite (same structure as CaTiO3) can form by dissociation of olivine in shocked martian meteorites (for example: shergottite Dar al Gani 735) recording extreme pressure and temperature conditions of at least 25 GPa, 700°C.

#MinCup25 #Calcite #Perovskite

Photograph of a cluster of milky white rhombohededral calcite with bright green crystals of mottramite. Location: Tsumeb mine, Namibia. Image credit: Dan Weinrich, Geoffrey Krasnov

Image of two brown, pseudo-cubic perovskite crystals. Location: Rocca Sella dikes, Italy. Image credit: Matteo Chinelatto

Calcite and perovskite may be battling it out in #minCup25 today, but they can be friends too. Here's an image of a layered rock with perovskite (dark brown) and clear blebs of calcitic carbonatite melt, and spiky crescumulate calcite crystals. This strange rock is from one of the Benfontein kimberlite sills in South Africa. Image is about 15mm wide. Sample is in the #Hunterian museum collections in Glasgow. #ThinSectionThursday #Geology #perovskite #Calcite #mineralogy

A microscope view of a rock in thin-section. The rock is moptly made of two minerals: dark brown-to black perovskite, and colourless clear calcite. The proportions of the two minerals show some layering/banding, and some layers have spiky crystals, or blobs of calcite.

#MinCup25 More reasons to vote for the incredible #calcite and its stunning crystallographic diversity. In Viktor Goldschmidt's monumental "Atlas der Krystallformen" calcite alone gets 153 plates showing different forms and habits. Enjoy them all here, although it may take a while! 🤩 😂 🤓
https://archive.org/details/atlasderkrystalltaf02gold/page/3/mode/1up

@MineralCup

#Geology #Mineralogy #Crystallography

A plate in an old book, featuring beautiful precise line drawings of complex crystal forms.

#MinCup25 More reasons to vote for the wonderful #calcite. Does any mineral, or any crystalline phase, show as much diversity of habit as calcite? In Matthew Forster Heddle's epic "Mineralogy of Scotland" he illustrates 29 whole-page plates of calcite habits just from Scotland. Enjoy scrolling through them here:

https://archive.org/details/mineralogyofscot01heddrich/mineralogyofscot01heddrich/page/n251/mode/2up

@MineralCup

#Geology #Mineralogy

#calcite

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