interesting find, not exactly sure what it is though

[fuss]

Lake Michigan beach find, so likely glacial deposit. It has a fine grain mix of green, red and white material in color for the exterior (only really seen under high 10x magnification) and a really nice looking thick midsection interior of translucent teal/green quartz( I think). whats interesting is the radiating fracture pattern. hardness of the quartz like interior is around 7 and exterior is 4-5ish. There is calcite as well mixed in this rock as well. The acid test only showed small spots of fizzing where there is known calcite.

So does the teal green stuff look like quartz ? to me it kinda does not especially in color and odd radiating fracture patterns, was thinking celestine but it seems harder like a quartz

 

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[stdenis_jd]

wow, I could be wrong but I think what you have there is prehnite and calcite in a basalt seam. The "step" patterns are indicative of calcite and prehnite does tend to crystallize acicularly.

any fluorescence? Try long and short wave both and take some awesome pics like you usually do so I can drool over it lol. Both prehnite & calcite can fluoresce, so you might have a really awesome UV specimen

 

[fuss]

Surprisingly it does not fluoresce very well under either LW or SW, the calcite does a bit but not very bright. Ill take some shots this evening.

 

[fuss]

LW UV image shows some of the calcite fluorescing white, unless something behind it is fluorescing and reflecting back through the calcite which is mostly a clear variety. There is a red spot could also be calcite but not sure. I believe the blue areas are mostly reflection of the UV light. There are a few green spots that the camera couldn't seem to reproduce the color and rendered them a dull yellow/whitish. Second shot is standard lighting. Still think prehnite is a possibilty? Thx.

I will be posting a bunch of fluorescent rocks and minerals as soon as I get to photographing them.

 

[stdenis_jd]

Does that host rock (the crust) look like basalt or rhyolite to you fuss? I'm not sure it isn't rhyolitic, but either way I still think it's prehnite. It's a tight seam/nodule so those radiating patterns are probably botryoidal cross-sections.

UV is never a perfect diagnostic test as not all fluorescent minerals will always fluoresce - case in point: fluorite - MOST of it doesn't fluoresce lol...the pink fluorescence is probably calcite.

Not sure if it's a rhyolitic, basaltic or granitic nodule/seam but I'm sticking with calcite & prehnite. You could break off a chunk of just the unknown mineral being careful to keep it pure (no crust, no calcite) and do an SG test....

 

[stdenis_jd]

here's a cross-section of prehnite:

 

[fuss]

it really does not look like an igneous exterior to me, it may be though. here is a close up of a different piece as well as pyrite? bits I didn't notice until now from another of the pieces that I broke off.
Ill go with your call of prehnite till proven otherwise. SG are a pain with what I have to do them with..lol..trying to tie a thread around a tiny mineral results in a lot of cursing..