ID help (MI serpentine?)

stdenis_jd

Hero Member
May 7, 2015
513
576
West Lower Peninsula, MI
Primary Interest:
Prospecting
Curious to see some opinions on this one. Found it in a gravel pit in North central lower peninsula of Michigan. It's the green one, can post pics of a slab if it is helpful. My first thought was a form of serpentine, but I don't have any first hand experience ID'ing it sinc 20170611_140141.jpg e I've never seen anything like it around here (gotta love dem glaciers!)

Grainy texture
Somewhat conchoidal fracturing, leaning toward his an uneven fracture pattern.
Hardness is about 6.
Fairly heavy/dense, solid build (no natural pitting or irregularities).
Opaque, no translucency.
It's looking like it will take a fantastic shine too, love the black stripes in it :-)

P.S. the black ones are mahogany obsidian, pink is Kona dolomite, red & white are Michigan puddingstone (jasper & white quartz sand conglomerate), and green/blue is chrysocolla)
 

Eu_citzen

Gold Member
Sep 19, 2006
6,484
2,111
Sweden
Detector(s) used
White's V3, Minelab Explorer II & XP Deus.
Primary Interest:
Prospecting
Post pics of the rough. Slabs don't do us much good, can't see the luster.
To hard for serpentine.

If you'd said it was translucent I'd gone with: Epidote, Diopside or Aegerine.

Opaque, well...? Turquoise? But it seems unlikely to have outlived glacial transport, but hey, what do I know?
 

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stdenis_jd

Hero Member
May 7, 2015
513
576
West Lower Peninsula, MI
Primary Interest:
Prospecting
The luster might be altered from the mineral oil from my slab saw. Dried it off pretty good tho.

Retested the hardness and it's definitely 5.5-6.0 max. 5.0 won't scratch it
 

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Eu_citzen

Gold Member
Sep 19, 2006
6,484
2,111
Sweden
Detector(s) used
White's V3, Minelab Explorer II & XP Deus.
Primary Interest:
Prospecting
I'm thinking Hornfels or another kind of rock. Not a mineral, really.
 

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