pocketfullarocks
having dreams about rocks
I love being a rock and mineral nerd!
Member since March 2019
Posts: 60
|
Post by pocketfullarocks on Mar 4, 2019 21:14:29 GMT -5
My cousin found this rock on the beach on the west side of Aruba. It is very dense and smooth. I read up on the island and its geology, which was volcanically formed. After a google image search, I was thinking Banded Iron Jasper (I found photos very, very similar to this rock) however, since BIJ is made up of hematite or magnetite, I was stumped when this produces nothing on a streak test. I took it to the club show and others agreed on BIJ but equally stumped on the streaklessness. I did a sorta hardness test trying to see what my 80 grit wheel did and it barely scuffed it. Another website stated it was Quartzite (which made me go hmmmmm???) or Petrified Wood (also offered up by my peeps, but noted that there is no sign of any cellular composition that would signify wood) When I get a chance to get to the club again, I will be cutting it on the bias, since my cousin requested I cab a pendant that way for his wife (and I get to keep the rest!) so I will be back with photos of that later. Thanks for any help! (edit note: sorry for the blurriness from unsteady hands I can try to do better if necessary; in bottom image, the stone is wet)
|
|
|
Post by fernwood on Mar 5, 2019 5:24:59 GMT -5
Banded Quartz? I find similar where I live.
|
|
jimaz
spending too much on rocks
Member since July 2018
Posts: 460
|
Post by jimaz on Mar 5, 2019 9:40:01 GMT -5
Almost looks like petrified wood.
|
|
victor1941
fully equipped rock polisher
Member since November 2011
Posts: 1,959
|
Post by victor1941 on Mar 5, 2019 20:33:46 GMT -5
This looks like petrified wood to me. I don't know how much cellular structure remains if you have complete replacement.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Mar 5, 2019 22:10:39 GMT -5
Not really any petrified wood on Aruba, unless it was imported there by some other means (e.g., ship's ballast). Aruba's volcanism all happened under the sea, causing uplift and only exposed after erosion. Quartz, chert, hypersthene and feldspars in various forms are present there, and all can occur banded, so I'd do a scratch test to see if you can narrow it down.
|
|