|
|
Post by sheltie on Mar 14, 2013 8:47:21 GMT -5
I collected about 25-30 lbs of what I thought was green banded rhyolite near Bouse, AZ when I was at Q this year. All were obviously banded and all were green on the outside. However, when I've slabbed them, all were black and white with similar patterns. Does anyone know what these are? I've heard zebra stone before but think that's just because no one knew and they look like a zebra.  |
|
snuffy
Cave Dweller 
Member since May 2009
Posts: 4,319
|
Post by snuffy on Mar 14, 2013 9:05:06 GMT -5
Basidian?
snuffy
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Mar 14, 2013 9:56:37 GMT -5
put some pool acid on it. Looks like marble to me. Marble fizzes.
|
|
Minnesota Daniel
freely admits to licking rocks
A COUPLE LAKERS
Member since August 2011
Posts: 891
|
Post by Minnesota Daniel on Mar 15, 2013 1:24:55 GMT -5
It's black, but turns green (dark I assume) with exposure/weathering? That can't be too many things. Usually the color is on the inside. Are you sure it's really black, and not actually very very dark green? What color does it streak?
|
|
|
|
Post by sheltie on Mar 15, 2013 8:29:00 GMT -5
It's black and the streaks are white.
|
|
Minnesota Daniel
freely admits to licking rocks
A COUPLE LAKERS
Member since August 2011
Posts: 891
|
Post by Minnesota Daniel on Mar 15, 2013 10:46:50 GMT -5
You mean when you scratch it on a streak plate the streak is white? I use the back of a ceramic tile as a streak plate. I would have guessed the streak to be either black or green.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Mar 15, 2013 14:08:33 GMT -5
have you acid tested it yet? I have black limestone of some sort that looks very similar that came from that area.
Even vinegar will react. If you get bubbles then you have limestone.
|
|
|
|
Post by sheltie on Mar 15, 2013 14:17:22 GMT -5
You mean when you scratch it on a streak plate the streak is white? I use the back of a ceramic tile as a streak plate. I would have guessed the streak to be either black or green. I don't think you are looking at the same thing I am. To simply even further, the "color" other than that which dark are the white streaks to which I refer. |
|
|
|
Post by sheltie on Mar 15, 2013 15:37:51 GMT -5
have you acid tested it yet? I have black limestone of some sort that looks very similar that came from that area. Even vinegar will react. If you get bubbles then you have limestone. No bubbles with vinegar. |
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Mar 15, 2013 20:33:33 GMT -5
What Danial means about streak is this:
Take a piece of the stone. Scratch on the back of a porcelain tile. The rough unglazed porcelain will remove a "streak" of material. This describes the "streak test". Many rocks will streak a color entirely different than we see when looking at an entire stone. For instance Hematite streaks red despite the almost black color. It is one of the diagnostic tests used similar to my acid test.
So, do you have an old porcelain plate or dish or perhaps a leftover tile from some tile work? The un-glazed under-surface is the area to check "streak" on.
[edited to add] or as snuffy says below - the underside of the tank lid on your commmode! You definitely have one of those!!
|
|
snuffy
Cave Dweller
Member since May 2009
Posts: 4,319
|
Post by snuffy on Mar 15, 2013 20:45:33 GMT -5
Still looks like basidian to me.
snuffy
|
|
Minnesota Daniel
freely admits to licking rocks
A COUPLE LAKERS
Member since August 2011
Posts: 891
|
Post by Minnesota Daniel on Mar 16, 2013 1:17:05 GMT -5
Still looks like basidian to me. snuffy I thought you were saying basidian like a little kid says pusghetti, just to be funny. You mean basidian, not obsidian. Yea, it does sort of look like basidian. There still needs to be some explanation for why the exposed outside of it looks greenish. Some basalt does look greenish I suppose. |
|
snuffy
Cave Dweller
Member since May 2009
Posts: 4,319
|
Post by snuffy on Mar 16, 2013 7:29:20 GMT -5
I've seen some beautiful points made out of basidian.Cant google just basidian,have to use basidian,basalt.I'm not saying thats what his is,just that it looks like it.  snuffy |
|
|
|
Post by sheltie on Mar 16, 2013 11:25:09 GMT -5
Wow, you really CAN teach an old dog new tricks! I have some ceramic tile left over from when my house was built and I took a piece of that as well as the rhyolite to give it the streak test. Unfortunately, the underside of the tile has been treated with some sort of brown substance and nothing is going to penetrate it. Fortunately - and unexpectedly - when I retreived a baggie of the "black" banded rhyolite, and took it out to do the test, it was green! Not an emerald green or remotely close to it, but definitely a darker green. I don't know what it will be like when polished, but when dry there is no doubt. When it came off the saw it was black and I would suspect that when polished it will revert to close to that. Only time, and polishing will tell.
|
|
snuffy
Cave Dweller
Member since May 2009
Posts: 4,319
|
Post by snuffy on Mar 16, 2013 11:37:18 GMT -5
The underside of a ceramic commode tank lid will work too.Iguess most are plastic now.
snuffy
|
|
Minnesota Daniel
freely admits to licking rocks
A COUPLE LAKERS
Member since August 2011
Posts: 891
|
Post by Minnesota Daniel on Mar 16, 2013 21:22:06 GMT -5
OK then, polish it and let's see what it looks after that.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Mar 17, 2013 22:18:14 GMT -5
I am going to see if we have any porcelain tile from discontinued product lines at work. If we di I will cut up a bunch of pieces and share.
|
|
