#GeoPicture of the day: Amethyst

For all its beauty, amethyst is a fairly common variety of quartz. This here isn’t even a particularly special image, it’s how amethyst looks like most of the time. What is it about this mineral that makes it so special? Quartz itself is the second-most-abundant mineral in Earth’s crust. Amethyst is one of the more common of the quartz varieties. Amethyst usually

#GeoPicture of the Week: Odyssey hits 60,000 Mars orbits

This image shows, in false color, the region around Gale Crater on Mars. It was taken by the 2001 Mars Odyssey spacecraft – but we just call it Odyssey. Odyssey has been orbiting the Red Planet for 14 years, 5 months and 20 days, recently celebrating a whopping 60,000 orbits around the planet, taking pictures and making valuable observations in the process. It currently

GeoPicture of the Week: Crinoid Fossils

Crinoids are marine animal (not plants) that have been around since the late Cambrian, some 500 million years ago. Crinoids usually have a stem used to attach themselves to a substrate, but many live attached only as juveniles and become free-swimming as adults. They are very fragile and require specific conditions to be preserved, so fossils like this one are very

GeoPicture of the Week: Volcanoes on Five Worlds – Venus’ Maat Mons, Earth’s Karymsky, Mars’ Olympus Mons, Io, and Enceladus

Image via Reddit.

GeoPicutre of the Week: Fossilized crinoids

This picture of fossilized crinoids was taken at the Sternberg Museum of Natural History, in Hays, Kansas. Crinoids are marine animals that are still alive today, even though their ancestors emerged during the early Cambrian, some 540 million years ago. They are echinoderms, related to starfish and sea urchins. They feed by filtering small particles of food from the sea

GeoPicture of the week: Mimetite

Mimetite, whose name derives from the Greek which means “imitator” is not really like any other mineral I’ve seen. It’s basically a lead arsenate chloride mineral which forms as a secondary product in lead deposits. It has no major uses, being a minor ore of lead, being usually gathered by collectors. It’s not used as a gemstone because of its

GeoPicture of the week: Giant Dragonfly fossil

This is a Cast of an original fossil of a Meganeuridae. If you’re scared of dragonflies, brace yourself for this: these extinct insects from the Carboniferous period measured up to 70 cm. They are the largest known species of flying insect. Controversy has prevailed as to how insects of the Carboniferous period were able to grow so large, especially considering

GeoPicture of the day: Titanium

Believe it or not, this is actually titanium, though not natural. It was obtained through a process called iodide process (or crystal bar process), unlike natural titanium, which is usually found chemically bonded in various ways found in rock ores. For more information, you should really check out this video (it’s actually a series with many other ones).

GeoPicture of the week: Elbaite, cleavelandite, and quartz mined from California’s Tourmaline Queen Mine

  Elbaite is a type of tourmaline, a sodium, lithium, aluminium boro-silicate. Cleavelandite is a type of albite feldspar.

GeoPicture(s) of the week: Columnar basalt

This week, there’s not going to be a picture, but rather a series of picture, because you just can’t sum up the beauty of columnar basalts in a single picture. Basalt is one of the more common extrusive igneous (volcanic) rocks. But how can these hexagonal columns take form? There’s no photoshop, no cutting, so how are these formed? The key

GeoPicture of the week: Mount Fuji

This is “just” a view of Mount Fuji – the highest mountain in Japan, actually a stratovolcano

GeoPicture of the week: folds at Mt. Head

In geology, folds are formed when originally horizontal layers of sedimentary rocks are bent and/or curved as result of acting temperatures and pressures. This is an absolutely stunning example of fold formation – click the pic for full size.

GeoPicture of the week: Crocoite from Tasmania

Crocoite is a fairly rare mineral in many parts of the world, consisting of lead chromate, PbCrO4. The relative rareness comes from the way it forms: it requires an oxidation zone of lead ore bed and presence of what are called ultramafic rocks, which act as a source of chromium. Ultramafic rocks are 90% mafic minerals (dark colored, high magnesium and iron content)

GeoPicture of the week: Baryte on fluorite

What you are looking at is a picture of a baryte crystal growing on fluorite; the two minerals have not been cut or polished in any way, it is just the way they naturally are. Fluorite (or fluorspar) is a mineral made out of Calcium and Fluorine while Baryte is literally barium sulfate. It has an orthorombic, cubical symmetry. Absolutely

GeoPicture of the week: two tectonic plates

This week’s picture shows the Eurasian and the American tectonic plates, as seen from underwater. In a way, you could say this is the edge of the Earth