|GSN field trip Day 2: We've taken a few Majuba Hill samples out of the bag.|
|We'll now take a look at the farthest right sample, having already seen|
Rocks #1 & #2 and Rock #3.
|One side shows a weathered surface, with dark brown iron oxides and the copper carbonates malachite and azurite.|
|A fresh surface of the same rock.|
|Zooming in on the fresh surface, we can see that we indeed have yet another sample of rhyolite porphyry:|
|What's really interesting about this rock is the white to gray matrix.|
|And here's another surface of the rock, one showing a moderate amount of reddish brown iron-oxide (hematite + jarosite), a pale bluish green copper mineral (or combo of minerals), and black tourmaline.|
And that's the last of our rhyolite porphyry samples, at least of those that haven't been brecciated!
Rhyolite Porphyry from Majuba Hill I
Rhyolite Porphyry from Majuba Hill II
Rhyolite Porphyry from Majuba Hill III (this post)