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
2. rhyolite
hardness= under3
streak= reddish
non magnetic
non fluorescent
no reaction to HCL
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
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
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
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
2. rhyolite
hardness= under3
streak= reddish
non magnetic
non fluorescent
no reaction to HCL
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
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
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
Amazon Forum Fav 👍
Last edited:
