Applying to join this forum, you HAVE to activate your membership in YOUR email in the notice you recieve after completing application process. No activation on your part, no membership.

Please login or register.

Login with username, password and session length
Advanced search  


Welcome new members & old from the Lapidary/Gemstone Community Forum. Please join up. You will be approved after spam check & you must manually activate your acct with the link in your email

Congratulations to Bobby1 and his Brazilian Agate Cab!

Another cabochon contest coming soon!

Pages: [1]   Go Down

Author Topic: Tiny thundereggs in mystery matrix  (Read 50 times)

0 Members and 1 Guest are viewing this topic.

R.U. Sirius

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 264
  • asleep at the grinding wheel
Tiny thundereggs in mystery matrix
« on: May 09, 2023, 04:23:52 PM »

Today I cut in half this irregular rock that was full of embedded spheroids with silica-filled cores - really a bunch of grape-sized lithophysae! Some beautiful red staining and even water lines are evident if you look carefully.

What confuses me is the matrix. It's not your typical rhyolite. Feels gritty, and is relatively dark with subtle green colour to it - more on the olivine-rich ultramafic end.

Does anyone here recognize it in terms of locality?

First image shows the sawn face, second one is the rough, both wet.


  • Administrator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3182
Re: Tiny thundereggs in mystery matrix
« Reply #1 on: May 10, 2023, 09:44:01 AM »

 These come from lots of places an are well studied. The green is celedonite .
Pages: [1]   Go Up

Page created in 0.1 seconds with 29 queries.