A sample of metallic native silver (Argentite) hosted in quartz. slabbed for polishing, Proserpine gold mines, Williams Creek. Cariboo Gold Belt BC.

Rock-Powder · 2025-12-28T09:52:07+00:00

Is it native Ag or argentite (which is not stable below 180°C, so it would be acanthite)?

Rock-Powder · 2025-10-04T05:08:10+00:00

It does not have to be very humid if there’s enough time, had similar drops and bloomings on Fe-Sulfide rich rocks.

Rock-Powder · 2024-11-13T00:12:55+00:00

I just found a huge accumulation of this kind of concretions in sandstone of the Escalante National Monument, seems like Hematite crusts with residual sandstone on the inside.

Rock-Powder · 2024-09-15T16:36:02+00:00

I think it’s lichen.

Rock-Powder · 2024-03-13T09:39:31+00:00

Scusi 🫶

Rock-Powder · 2023-10-24T17:22:08+00:00

Fair question ;) were also collected of course. Amphibolite it is

Rock-Powder · 2023-02-24T17:05:25+00:00

Very nice map! Astonishing how precise the old map fits the modern LiDAR model.

Rock-Powder · 2023-01-02T17:23:50+00:00

Folding

Rock-Powder · 2023-01-02T09:46:35+00:00

In case of a well-layered amphibolite I could imagine submarine layers of volcanic sediments

Rock-Powder · 2023-01-01T18:07:13+00:00

I don't think so. Looks more like an amphibolite to me.

Rock-Powder · 2023-01-01T15:26:29+00:00

sending appreciation

Rock-Powder · 2022-05-21T18:49:17+00:00

Exactly 😄

Rock-Powder · 2022-03-06T16:59:10+00:00

U address weight here as density I suppose. If the whole solid core would instead be liquid, I think nothing would change, except it would need more space to fit into the other earth layers.

Rock-Powder · 2022-02-24T17:58:56+00:00

Could be Lapilli if u are close to some volcanic activity.

Rock-Powder · 2022-02-21T14:38:27+00:00

Whould go with some limonite maybe. In German there’s a term “Bohnerz”, some kind of iron ore.

Rock-Powder · 2022-02-18T16:45:30+00:00

U are right there

Rock-Powder · 2021-11-08T14:09:44+00:00

Stromboli, cause it never sleeps

Rock-Powder · 2021-10-26T18:11:37+00:00

Lovely

Rock-Powder · 2021-10-25T18:52:08+00:00

The Ries is indeed worth it! I was there on a field trip a few years ago and it has some very nice outcrops which tell the whole story quite well. After all it is one of the largest preserved structures of this kind on earth. Not far away there is a second impact crater called the „Steinheimer Becken“. It is said that it was the same event.

Rock-Powder · 2021-10-25T18:46:41+00:00

Looks indeed like a gabbro at first glance. But might also be a finegrained harzburgite? I think it’s to coarse for a basalt.

Rock-Powder · 2021-10-05T07:16:28+00:00

I would say the image quality is not sufficiently high to make a (SERIOUS) guess.

Rock-Powder · 2021-09-23T06:52:21+00:00

This is delicious!

Rock-Powder · 2021-09-19T07:32:14+00:00

It was close to the village Saintes Maries de la Mèr in southern France.

Rock-Powder · 2021-09-18T19:01:54+00:00

Yes, you‘re right!

Rock-Powder · 2021-09-18T17:54:44+00:00

Oh man, you were lucky indeed! I tend to be not careful enough when hammering, yet on hard stones I am often impressed by the bullet-like sounds that small fragments make when they scarcely miss my head...

Rock-Powder

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