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Petr Hykš's user avatar
Petr Hykš's user avatar
Petr Hykš's user avatar
Petr Hykš
  • Member for 7 years, 6 months
  • Last seen more than 3 years ago
13 votes
3 answers
7k views

What is the white coating "patina" we often see on deposited chalcedony/agate?

8 votes
1 answer
326 views

What is the best way to stay safe while photographing lightning storms?

8 votes
1 answer
988 views

What "g" would be needed to keep helium on Earth?

6 votes
0 answers
1k views

Could this be pyroxene twinning ? (thin section)

5 votes
0 answers
835 views

I have found this structure in thin section. What is it?

5 votes
2 answers
485 views

Muscovite with pleochroic halos?

5 votes
2 answers
5k views

How does quartz form in calcite veins?

4 votes
1 answer
326 views

Do you have any informations about fossil-rich cherts from Scandinavia?

4 votes
1 answer
478 views

I have found this fossil tooth, could it be pliosaur ? Or maybe theropod?

2 votes
1 answer
156 views

Pileus / velum & altocumulus / altostratus - classification problems

1 vote
1 answer
165 views

What exactly is ammonite?