Lessons in Greenstone

[yakker]

I've been collecting bunches of various shades and types of green rocks up above a local reservoir for a while now. Beyond just interesting, many of them are quite beautiful. I finally brought them to the Division of Mineral Resources here in town and got the low-down. All are part of what's known as the Catoctin Formation (Late Proterzoic period). In fancy terms it's called mineralized metabasalt, and the various minerals present in this mix are: chlorite quartz (the beautiful teal green shiny translucent pieces), actinolite (BB was right!!!) which looks a lot like schorl, albite (pale green and opaque), epidote- which comes in several varieties including avocado green (looks just like avocado in color), as well as blade-like micro (ish) crystals (I saw some really awesome local examples from mines and quarries which hadn't been pummeled by flood waters. It can be very dark, almost black-green, brilliant emerald green or kelly green), and last (and to a lesser degree)- magnetite. So. There we have it. Here are a few more pics- and others- for reference- are in my last post on 'Greens' Thanks for reading!







and these last two are for EU who wanted to see that one rock- this time hopefully closer...

 

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[shaman15771]

Cool Talker!

 

[Eu_citzen]

Kinda reminds me of chalcedony/quartz.

 

[BurntBear]

Awesome!

 

[DDancer]

Picked up some fine stuff there Yakker Picture in the second row rock on the bottom left corner with the blue green look appears to be a feldspar possibly amazonite. I like the speci with the radiant crystals.

 

[yakker]

Indeed- DD it is. Oddly, I found it along the shores of the Rivanna- and it shouldn't have been there. Perhaps dropped by someone... I seem to be the queen of finding things that aren't where they ought to be. First, Brazilian rutilated quartz and now amazonite...(ID'd by a local expert) Hmph.

 

[DDancer]

Kinda wonder if someone was cleaning out the closet and let those loose in the wild Nice additions to your collection though.