help id a couple common looking rocks

fuss

Hero Member
Joined
Jul 27, 2018
Messages
575
Reaction score
837
Golden Thread
0
Location
Wisconsin
Primary Interest:
All Treasure Hunting
These are beach finds from the shore of lake Michigan in SE WI. I have an idea as to the id on them but as usual with rocks its hard to be certain. So wondering if I can can get a little help.

1. I am guessing gabbro, amphibolite or peridotite though does not appear like other gabbro's I have seen.
Hardness= 2.5-3
streak= green though under a loupe its white powder mixed with green bits
non magnetic
no reaction to HCL
non fluorescent

gabbro or peridotite2.webp

Untitled1gabbro or peridotite.webp

2. rhyolite
hardness= under3
streak= reddish
non magnetic
non fluorescent
no reaction to HCL
amygdaloidal rock.webp

3. Augite mineral with some plagioclase and quartz
hardness= around a 3
streak=bits of dark green mixed with white powder
attracted to a magnet
no reaction to HCL
non fluorescent
hornblende.webp

4. some kind of calcite, magenta color tint with red "specks" and some green epidote maybe
hardness= 4
streak=white
does react strongly to HCL
not attracted to a magnet
some fluorescense red and green in one area
pink stone.webp

5.calcite= though harder and feels like gypsum in hand. feels soft and silky, like should be able to scratch with fingernail but cant.
hardness= 6
streak= white
does react to HCL though not vigorously
translucent
fluoresces yellow

soft quartz.webp

soft quartz2.webp

calcite yellow fl.webp
 

Last edited:
I'm not much help. I thought gabbro had larger grain size. Gary
 

Upvote 0

Top Member Reactions

Users who are viewing this thread

Back
Top Bottom