Erika Anderson
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andersonmineral.bsky.social
Erika Anderson
@andersonmineral.bsky.social
660 followers 110 following 580 posts
Former Curator of Mineralogy and Petrology. MSc in Volcanology. Views are my own.
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andersonmineral.bsky.social
The metamorphic mineral staurolite with its distinctive penetration twinning forming a cross. It’s positively delightful!! #MineralMonday #GeoscienceBluesky ⚒️🧪
Brown crystals forming a cross in white matrix. It sits on a black background. At the Sorbonne.
November 10, 2025 at 12:23 PM
andersonmineral.bsky.social
As cool and cute as sabre-toothed tigers are, at least I don’t have to fear staring down the maw of Smilodon populator these days. #FossilFriday ⚒️🧪
Looking down the jaw of mounted skeleton of a fossil sabre-toothed tiger with its mouth open. It stands on a wooden plinth on a wood floor among glass display cases. At the Muséum national d’Histoire naturelle.
November 7, 2025 at 12:43 PM
Reposted by Erika Anderson
diygeochemist.bsky.social
Oh my gosh. These are both super cool. Ilmenite is amazing, and I love titanium...but I think I'm gonna vote for the super unusual #Jadarite, which is a lithium borate.
mineralcup.bsky.social Mineral Cup & Ore Cup @mineralcup.bsky.social · 6d
#OreCup R1M3: It’s a battle of black and white as titanium ore #Ilmenite is pitted against lithium and boron ore #Jadarite.

vote: www.mineralcup.org/vote-results...
results:
www.mineralcup.org
November 5, 2025 at 8:56 PM
Reposted by Erika Anderson
eos.org
We're Team #Ilmenite today in the #OreCup! Not only did it enable Bob Ross's happy little clouds, it also may have helped flip the Moon's mantle. So versatile! 🔭🧪🌕

eos.org/articles/the...
November 5, 2025 at 6:25 PM
andersonmineral.bsky.social
Ah yes!! Another bacon specimen!! This time it’s banded aragonite. #MineralMonday #GeoscienceBluesky ⚒️🧪
Specimen that is a polished slab of white and pale and dark brownish pink stripes , resembling bacon. It sits on a grey background with the edges of another specimens and labels seen around it. Label to the bottom right says « D28 - BM.58818 Stalagmitic banded, polished Loket, Karlovarský kraj. Czech Republic » At the Natural History Museum London.
November 3, 2025 at 12:35 PM
andersonmineral.bsky.social
The answer is the iron ore hematite!! A streak is when you rub a mineral on a slightly rough surface to see what colour the powder left behind is. The streak helps identify the mineral, as it might be different than the colour of the specimen. #GuessTheGem #GeoscienceBluesky ⚒️🧪💎
andersonmineral.bsky.social Erika Anderson @andersonmineral.bsky.social · 13d
Another Tuesday Guess the Gem!! What mineral do you think these gems are? Hint: their streak would be red.
#GuessTheGem #GeoscienceBluesky ⚒️🧪💎
In the center are two gems, each on white foam in a white gem case. The one on the left is a round cut and the right is a long cabochon with two pointed ends in the east west direction. They are surrounded by lined up gem cases you can see the edge of. At the Hunterian.
October 29, 2025 at 11:40 AM
andersonmineral.bsky.social
Another Tuesday Guess the Gem!! What mineral do you think these gems are? Hint: their streak would be red.
#GuessTheGem #GeoscienceBluesky ⚒️🧪💎
In the center are two gems, each on white foam in a white gem case. The one on the left is a round cut and the right is a long cabochon with two pointed ends in the east west direction. They are surrounded by lined up gem cases you can see the edge of. At the Hunterian.
October 28, 2025 at 11:33 AM
andersonmineral.bsky.social
Another bright mineral!! The element sulphur makes these beautiful crystals. Be careful, sometimes the warmth of your hand can cause these sensitive crystals to crack. #MineralMonday #GeoscienceBluesky ⚒️🧪
Tall specimen consisting of many bright yellow sulphur crystals on grey matrix. It sits on a frosted plinth in front of a grey wall. An edge of another striped mineral, orpiment, can be seen at the top left. At the Royal Ontario Museum.
October 27, 2025 at 11:34 AM
andersonmineral.bsky.social
When first described, the perceived agility of the theropod Deinonychus antirrhopus helped catalyze the idea that dinosaurs were not as slow moving as previously thought. #FossilFriday ⚒️🧪🦖
Mounted fossil skeleton of Deinonychus antirrhopus on top of a wooden display case. At the Sedgwick Museum.
October 24, 2025 at 11:47 AM
andersonmineral.bsky.social
The answer to this Guess the Gem is peridot!! This is a variety of the mineral group olivine, frequently found in basalts (and found in some meteorites!). #GuessTheGem #GeoscienceBluesky ⚒️🧪💎
andersonmineral.bsky.social Erika Anderson @andersonmineral.bsky.social · 20d
Another Guess the Gem for you!! What mineral or variety do you think this gem is? Hint: this is the gem variety of a mineral commonly found in my favourite type of rock: volcanic.
#GuessTheGem #GeoscienceBluesky ⚒️🧪💎
Green irregular cut gem in a clear round gem case on beige foam. The case sits on a beige background. The top edge of a small white label can be seen on the bottom right. At the National Museum of Ireland.
October 22, 2025 at 11:16 AM
andersonmineral.bsky.social
Another Guess the Gem for you!! What mineral or variety do you think this gem is? Hint: this is the gem variety of a mineral commonly found in my favourite type of rock: volcanic.
#GuessTheGem #GeoscienceBluesky ⚒️🧪💎
Green irregular cut gem in a clear round gem case on beige foam. The case sits on a beige background. The top edge of a small white label can be seen on the bottom right. At the National Museum of Ireland.
October 21, 2025 at 11:32 AM
andersonmineral.bsky.social
The most delectable rhodochrosite!! Bright minerals make me very happy!! From bright butterfly wings to the plumage of birds of paradise, nature is a tapestry of rich colours. #MineralMonday #GeoscienceBluesky ⚒️🧪
Specimen showing large bright reddish pink rhombohedrons with small white to clear crystals of quartz on dark grey matrix. It sits on a frosted plinth in front of a grey wall. At the Royal Ontario Museum.
October 20, 2025 at 11:26 AM
andersonmineral.bsky.social
Skull of the Early Triassic amphibian Thoosuchus jakovlevi. Lots of surface texture preserved on it!! #FossilFriday ⚒️🧪
Triangular skull of Thoosuchus jakovlevi mounted on a display wall with part of the black silhouette of the creature behind it. There is also part of the blue silhouette of another animal on the beige wall. At the Hunterian.
October 17, 2025 at 11:53 AM
andersonmineral.bsky.social
The answer is tanzanite!! It’s a mineral only found in one area of Tanzania and it shows trichroism.
#GuessTheGem #GeoscienceBluesky ⚒️🧪💎
andersonmineral.bsky.social Erika Anderson @andersonmineral.bsky.social · 27d
Another Guess the Gem for this week!! What mineral do you think these gems are? Hint: its colour depends on which side of the crystal you are looking at.
#GuessTheGem #GeoscienceBluesky ⚒️🧪💎
Two gems in white plastic gem cases on white foam surrounded by the edges of other gem cases. The left gem is greyish blue oval-ish cut and the right is a dark purple blue rectangular-ish cut. At the Hunterian.
October 15, 2025 at 11:34 AM
andersonmineral.bsky.social
Another Guess the Gem for this week!! What mineral do you think these gems are? Hint: its colour depends on which side of the crystal you are looking at.
#GuessTheGem #GeoscienceBluesky ⚒️🧪💎
Two gems in white plastic gem cases on white foam surrounded by the edges of other gem cases. The left gem is greyish blue oval-ish cut and the right is a dark purple blue rectangular-ish cut. At the Hunterian.
October 14, 2025 at 11:25 AM
andersonmineral.bsky.social
Some beautiful spherical ferrian turquoise, also known by the variety names henwoodite or rashleighite. #MineralMonday #GeoscienceBluesky ⚒️🧪
Small spheres of bright turquoise turquoise on dark brown matrix in cavities of a rust coloured rock. It sits mounted on a black shelf. At the Sedgwick Museum.
October 13, 2025 at 12:25 PM
andersonmineral.bsky.social
The fierce carnivore Inostrancevia is one of the species of synapsids that went extinct in the Great Dying, known as the Permian-Triassic Extinction event. #FossilFriday ⚒️🧪
Mounted skeleton of fossil Inostrancevia with its body facing left. It’s skull shows large saver like teeth. It stands on a bed of shale fragments on a plinth with red plexiglass behind it. At the Royal Ontario Museum.
October 10, 2025 at 11:41 AM
andersonmineral.bsky.social
The answer is diopside!! Asterism is when inclusions (or sometimes twinning) cause refraction or reflection to concentrate light into a star shape. #GuessTheGem #GeoscienceBluesky ⚒️🧪💎
andersonmineral.bsky.social Erika Anderson @andersonmineral.bsky.social · Oct 7
Guess the Gem time!! What mineral do you think this gem with asterism is? Hint: sometimes called jasper or emerald, it is a different mineral.
#GuessTheGem #GeoscienceBluesky ⚒️🧪💎
Black sphere showing a white 4 rayed star (asterism) slightly off centre to the lower left. It sits on a frosted plinth with a number 4 on it. It sits on a grey background with the bottom of another plinth showing behind it. At the Royal Ontario Museum
October 8, 2025 at 11:26 AM
andersonmineral.bsky.social
Guess the Gem time!! What mineral do you think this gem with asterism is? Hint: sometimes called jasper or emerald, it is a different mineral.
#GuessTheGem #GeoscienceBluesky ⚒️🧪💎
Black sphere showing a white 4 rayed star (asterism) slightly off centre to the lower left. It sits on a frosted plinth with a number 4 on it. It sits on a grey background with the bottom of another plinth showing behind it. At the Royal Ontario Museum
October 7, 2025 at 11:31 AM
andersonmineral.bsky.social
It’s Geodiversity Day & Mineral Monday!! So I wanted to show you a rare mineral called carletonite, which is usually bright blue but seen here with a pink zonation. It was discovered here in Canada, at the mineral species rich Mont Saint-Hilaire. #GeodiversityDay #MineralMonday #GeoscienceBluesky ⚒️🧪
Specimen of carletonite with prisms of blue and pink all around. There is one large square crystal with a small blue square in the middle with pink on the outside on the upper right side of the specimen. It sits on a black background. At the Canadian Museum of Nature.
October 6, 2025 at 11:18 AM
andersonmineral.bsky.social
A herbivorous archosaur, Trilophosaurus buettneri, which if you look closely at its jaws has no teeth at the front of its mouth. It might have had some sort of beak. #FossilFriday ⚒️🧪
Mounted fossil skeleton of Trilophosaurus buettneri seen from the side. Its head faces the camera with its mouth open showing that the teeth end at the front of its jaws. Its feet sit in pale disks that look like sandstone that then sit on a greyish wooden shelf where parts of it are inset into the front of a grey riser. You can only see part of its long tail. At the Royal Ontario Museum.
October 3, 2025 at 11:39 AM
andersonmineral.bsky.social
If you like colourful minerals, check out crocoite!! #MineralMonday #GeoscienceBluesky ⚒️🧪
Specimen consisting of many long tabular crystals of bright orange crocoite at various different angles on a black shelf. At the Canadian Museum of Nature.
September 29, 2025 at 11:43 AM
andersonmineral.bsky.social
This pterosaur species, Scaphognathus crassirostris, was first described all the way back in 1831! Look at the teeth!! #FossilFriday⚒️🧪
Cast of an incomplete Scaphognathus in yellow beige rock. The spine, skull, and wing bones can be seen. The skull is on the top right edge showing large spaced out teeth. At Kelvingrove.
September 26, 2025 at 11:50 AM
andersonmineral.bsky.social
This chalcedony is so beautiful!! It looks like a modern art sculpture or something swept up in the wind. How does this form? #MineralMonday #GeoscienceBluesky ⚒️🧪
White chalcedony made up of the rounded long lengths resembling thick fibres making it look like a wad of string or cloth falling apart. Label on the bottom says “Chalcedony/SiO2/Locality Unknown”. At the Sedgwick Museum.
September 22, 2025 at 11:33 AM
andersonmineral.bsky.social
Real skull of Sue the T. rex!! Did you know the one on the full display is a cast that removed the distortion due to crushing that we see here. #FossilFriday ⚒️🧪🦖
Large T. rex skull seen from the front in a glass case. The right side is much flatter than the left. At the Field Museum.
September 19, 2025 at 11:22 AM