Erika Anderson
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andersonmineral.bsky.social
Erika Anderson
@andersonmineral.bsky.social
660 followers 110 following 600 posts
Former Curator of Mineralogy and Petrology. MSc in Volcanology. Views are my own.
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andersonmineral.bsky.social
Guess the Gem time!! What mineral do you think this gem is? Hint: in the past gems of this mineral were called rubies, though now the term refers to corundum. #GuessTheGem #GeoscienceBluesky ⚒️🧪💎
A pink oval cabochons mounted on a metal rod on a grey shelf with a grey background. There are some fractures in it. At the Muséum national d’Histoire naturelle.
November 25, 2025 at 12:37 PM
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Great little crystal of bright orange scheelite. It would be surprisingly heavy if you held it due to the tungsten in this mineral. #MineralMonday #GeoscienceBluesky ⚒️🧪
Bright orange crystal octahedra of scheelite in white crystals. It sits on a black background. Edges of a plexiglass label and white specimen can be seen to the upper right. At the Sorbonne.
November 24, 2025 at 12:20 PM
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The skull of a giant sloth, Megatherium americanum, from South America. This species went extinct, along with most other megafauna, in the Late Pleistocene Extinction Event thought to be caused by humans and changes in the climate. #FossilFriday
The skull of the giant sloth, Megatherium americanum, mounted on a metal rod on a wood plinth. Wood plinths with other specimens can be seen behind it. A white label sits to the lower left. At the Muséum national d’Histoire naturelle.
November 21, 2025 at 12:27 PM
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Guess the Gem!! What mineral do you think these two gems are? Hint: the blue one is irradiated and heated to get that colour.
#GuessTheGem #GeoscienceBluesky ⚒️🧪💎
Two gems on a beige background. The top is a large round light brown Portuguese-style cut gem. The bottom is a small bright blue oval cute gem. The edges of white labels can be seen at the top and bottom. At the Natural History Museum in London.
November 18, 2025 at 11:41 AM
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Have you ever heard of this mineral? Pachnolite was discovered in Greenland and the name translates to frost stone, which is a very cool name. #MineralMonday #GeoscienceBluesky ⚒️🧪
Specimen of pachnolite showing bright brown yellow sharp crystals in a cavity in white crystals. It sits on a frosted plinth on a glass shelf on a grey wall. The edge of a green and brown specimen on a plinth can be seen to the top left. The plinth has a label that says « Pachnolite/Pachnolite » on it.At the Royal Ontario Museum.
November 17, 2025 at 12:34 PM
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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
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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
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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
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
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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
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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
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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
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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
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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
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
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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
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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
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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
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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
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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
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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
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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
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One of the coolest hematite specimens I have ever seen, it’s wider than my hand!! It’s from Parkside, Cumbria, UK. #MineralMonday #GeoscienceBluesky ⚒️🧪
Specimen of hematite that is made up of round concentric segments that form donut shapes stacked on top of one another (3-4). Looks a bit like curled up pull bugs. It sits on a black shelf with the edge dark grey specimen seen next to it. At the Great North Museum: Hancock.
September 15, 2025 at 8:33 AM