Pseudomorph Starolite

[605dano]

Found this in some shist. Shape looks starolite,but I don't know what the mineral is that replaced it if it is a starolite at all.

 

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[Rific]

Found this in some shist. Shape looks starolite,but I don't know what the mineral is that replaced it if it is a starolite at all.

Can't help you on the ID but thats a very pretty one good find!

 

[Clay Diggins]

That's a retrograde alteration to mica. Pretty common with Staurolite but not a true psuedomorph.

Nice specimen. It looks like the material from Mora or Pillar, New Mexico. Look around where you found it and you will likely find garnet crystals.

 

[605dano]

Garnet crystals are common in the shist rock. Picture number 3 you see a couple , but they are all small. Mica fish are also present in a couple of places, but this is the first time I've seen crosses.

 

[Clay Diggins]

The Staurolite degrades to mica and eventually the mica degrades to clay. The mica didn't replace the Staurolite form like in a psuedomorph it is a product of the alteration of the Staurolite crystal itself.

New Mexico? Georgia?

 

[605dano]

South Dakota. Garnets, staurolites, and mica are very common here. When the staurolites degrade, is it a weathering process or temp. and pressure situation?