Jadee 20 Posted September 30, 2020 Share Posted September 30, 2020 Found this rock in a glacier moraine deposit in central Minnesota: the greenish rough part is hard - if I were to guess the Moh's scale rating it would have to be about a 7. The white rock coming out of the formation has a soft waxy feel to it (Moh's of about 4-5). I have never seen anything like this before. I'm scratching my head on this one Quote Link to post Share on other sites
Morlock 1,722 Posted September 30, 2020 Share Posted September 30, 2020 49 minutes ago, Jadee said: Found this rock in a glacier moraine deposit in central Minnesota: the greenish rough part is hard - if I were to guess the Moh's scale rating it would have to be about a 7. The white rock coming out of the formation has a soft waxy feel to it (Moh's of about 4-5). I have never seen anything like this before. I'm scratching my head on this one My guess would a feldspar conglomerate. That's my first impression and probably a wild guess at that. 1 Quote Link to post Share on other sites
d_day 350 Posted September 30, 2020 Share Posted September 30, 2020 I’m thinking unakite, which is epidote (Green) and plagioclase feldspar (pink). Just a guess based on the photo and the information given. 1 Quote Link to post Share on other sites
4meter 201 Posted September 30, 2020 Share Posted September 30, 2020 Its a chunk of granite. The green staining is most likely algae. Try soaking the sample in some strong ammonia (not Windex) for a few days, the green should come out. Quote Link to post Share on other sites
Jadee 20 Posted October 2, 2020 Author Share Posted October 2, 2020 Mr. 4Meter, I did soak it in an 1 teaspoon of CLR and 1 gal of distilled water for about 5 days and gave it a good scrubbing with a firm tooth brush. I worry that if I soak it in anything stronger that white part would get ruined, it is so soft. Not so sure if I want to keep it or use it for a garden rock? Quote Link to post Share on other sites
BMc 1,044 Posted October 2, 2020 Share Posted October 2, 2020 2 hours ago, Jadee said: Mr. 4Meter, I did soak it in an 1 teaspoon of CLR and 1 gal of distilled water for about 5 days and gave it a good scrubbing with a firm tooth brush. I worry that if I soak it in anything stronger that white part would get ruined, it is so soft. Not so sure if I want to keep it or use it for a garden rock? Why would "You", want to, "keep it"? IMO, it would make a swell garden rock! 1 Quote Link to post Share on other sites
bigrex 60 Posted October 5, 2020 Share Posted October 5, 2020 Who knows, white stuff could also be calcite, depends on the hardness. Quote Link to post Share on other sites
Morlock 1,722 Posted October 5, 2020 Share Posted October 5, 2020 6 hours ago, bigrex said: Who knows, white stuff could also be calcite, depends on the hardness. Add a few drops of warm vinegar onto the two different colored parts. If one fizzes, it's calcite or limestone. It will be a slow reaction so you'll have to wait a few minutes. Quote Link to post Share on other sites
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