#biotite

[amethysthands]

I <3 minerals

[mineralsandsomerocks]

Zircon in Biotite Schist

Locality: Astore Valley, Astore District, Gilgit-Baltistan, Pakistan

[oldearthminerals]

Zircon Crystal on Biotite Schist, Calcite & Carbonatite Matrix.

https://www.oldearthminerals.com/shop/p/zircon-crystals-wit-biotite-on-matrix-1-aymdw-5rty8-ccdet-fsrpt-9c2x5

#zircon #crystals #crystaltok #minerals #biotite #fluorescentminerals #mineralspecimen

[sagittariusboyfriend]

oh man oh man i found the most beautiful seam of porphyry (some of it basically glomeroporphyritic) in the dacite-rhyolite mountains behind my parents place! i was out for only two hours and lugged a big heavy piece home with me along with some smaller ones:

look at that huge cryst on the left one.

it has some nice biotite in it as well. it was really fuckin wet (and sweaty!!) though and i just about made it back before it started pouring. looking forward to tomorrow to see how it looks when it dries in the sun

also, looks completely different from the very red dacite (im now thinking that one was more of a rhyolite?) i got from the same area last year, just maybe 100m apart.

the bedrock it came from. look at those three color shifts, left to right, dark to beige to spotted. this is a magma rich in felsic minerals that probably cooled real slow at first, then got mixed up with a mafic one via plate subduction, heated back up and had a big devastating yellowstone-like eruption ~1,9 billion years ago. add some tectonic drift, accretions, isostatic rebound, then some magma intrusions.

[rocksnrocknroll]

look at this perfect little biotite heart!!!! happy late valentine’s day 🧡

[n0rtist]

This new rock line is based off of the discontinuous series of the Bowen's Reaction Series. The Bowen's Reaction Series is a chart of the different kinds of minerals one can expect from basaltic magma cooling down in different temperatures. The discontinuous series in there describes a progression where silicate minerals crystallize in different patterns dependent on the cooling temperature. If the cooling temperature is still pretty high, the silicate are spaced apart, but if the cooling temperature is much colder, they can join into a sheet. Also btw, silicates aren't triangular but rather tetrahedral (triangle pyramid).

Oligem (Rock): Surprisingly, the crystal part of an Oligem is usually warm to the touch unlike the rest of their body. They sometimes join their legs together like a ring to concentrate and make their crystal glow temporarily.

Petroxene (Rock): Petroxenes appear to like hugging warm bodies as they are much cooler to the touch than Oligems are. When Petroxenes lose chunks of their arms, they can grow them back, but the new arms are shaped differently.

Bienite (Rock): Bienite's joints can regularly bend because, up close, they joints are connected by thin overlapping sheets. Unlike that of their previous stages, Bienite bodies do not leave any heat signatures.

[melusina]

Behold. The most perfect biotite

[drrockclub]

Biotite mineral

This black mineral is made up of many super thin sheets which is characteristic feature of mica mineral group. You can literally peel off these sheets like a sticker. Biotite owns its black colour from iron element (Fe) and it is a diagnostic feature for this mica mineral. It is very soft, and you can easily crumble thin sheets of biotite in your hands to make a black glitter.

Example from rock outcrop in central Australia.