ID help - White w/ Purple Circle & Green Sparklies

[ScribbleMuse]

Yeah, my title description is probably showing my ignorance, but I really am trying with this stuff! I'm concentrating mostly on rocks/minerals lately since that's where all my luck seems to be and I'm finding myself more and more fascinated. However, there is a major steep learning curve for me... as in going from the term "sparklies" to a definitive crystal description.

Most others are simple for me right now; I haven't found a lot of really oddball things but this one is a little off base for my usual stuff so far. Here are the pics I have... I really have no other data because it's so small I'm not sure how to do any of the typical streak tests and such without potentially cracking/removing the crystals.

Thanks in advance!

Found in the same super-low creek bed I'm getting all my agates & jaspers, glacial till and debris (I believe anyway), Central Wisconsin.

 

[Eu_citzen]

Marcasite (a form of low temperature pyrite) would be my first guess.

 

[ScribbleMuse]

Thanks yet again, Eu_citizen! Marcasite is one of my favorite minerals based on photos in the books and sites in the books I've been reading, and honestly would never have considered it since the photos always look more yellowish in color. However, I can see that the crystals on this specimen are so very small/thin that the color could appear much greener with the purple background. As for the purple background, is that just part of the crystals? It looks very neat in real life with the very clear purple border set against the white of the matrix (is that the right term?). Also, I apologize for not noticing the differences in the color tones of the photos; the very first photo with the ruler is the exact shade as the stone itself, more than the yellowish-toned photos. I meant to post just the pics that match the tone but was so late I was about to pass out on the keyboard.

I wish you could teleport to my house real quick and just point and ID the rest of my rocks. I swear I've somehow managed to haul home a zillion-bajillion tons over the last two weeks, and while I'm getting better at coming up with potential IDs for my most common finds, I'm no where near the point where i can be confident.

I figure that I need to attempt to ID as much as possible before relying on this forum or others for immediate help, but it sure is tempting sometimes to just flood the board with hundreds of desperate pleas for help!

 

[Eu_citzen]

I know, but I was guessing on it since the rock looks like it could be sandstone or otherwise sedimentary.
Marcasite does occur in a isle east of me, mostly in sandstone.

There are other alternatives, but I don't think you'd even want to try to do some tests. It'd be a shame for the specimen.

A thin knife could at best be used for a hardness test, on a side not so easily visible.
But I don't think I'd do it. Better save it and look when you've gained experience.

lol, Sweden is a fair bit from Wisconsin indeed!

I know one guy, when he came out of school he shipped home a couple of pallets of rock.
Since I also do cabochon cutting and faceting it wouldn't surprise me if I did have a ton of rock at home at this point, to.
(Literally!)

I remember when I was new I did also ask a lot. I did always put myself in a "quiz" like position first.
I did guess what it SHOULD be. If it wasn't what I expected I'd ask how they came to that conclusion.

A wise man once told me; "It is better to ask stupid questions then to remain stupid!"
Those words I try to live by. So, ask away.
Though try to limit the posts to 10 per day, I also want to have a life outside this forum!

 

[ScribbleMuse]

I know, but I was guessing on it since the rock looks like it could be sandstone or otherwise sedimentary.
Marcasite does occur in a isle east of me, mostly in sandstone.

There are other alternatives, but I don't think you'd even want to try to do some tests. It'd be a shame for the specimen.

A thin knife could at best be used for a hardness test, on a side not so easily visible.
But I don't think I'd do it. Better save it and look when you've gained experience.

lol, Sweden is a fair bit from Wisconsin indeed!

I know one guy, when he came out of school he shipped home a couple of pallets of rock.
Since I also do cabochon cutting and faceting it wouldn't surprise me if I did have a ton of rock at home at this point, to.
(Literally!)

I remember when I was new I did also ask a lot. I did always put myself in a "quiz" like position first.
I did guess what it SHOULD be. If it wasn't what I expected I'd ask how they came to that conclusion.

A wise man once told me; "It is better to ask stupid questions then to remain stupid!"
Those words I try to live by. So, ask away.
Though try to limit the posts to 10 per day, I also want to have a life outside this forum!

Ha... that means that when I get reasonable equipment setups to do the carving that I originally intended to do before falling into the hole of "true" mineralogy as well, I can STILL pester you with questions about the things you probably will eventually help confirm for me (or more likely, show me the error of my ways... lol).

I am definitely hitting the next mineral show in our area, which is the first weekend of October. I'm a reader and a self-teacher by nature, but there are a few subjects that I think I require hands-on remedial education with first, and this is one. For instance, I have a few specimens I've cleaned up to a sparkling beautiful state which make me much prouder than I ought to be, but I'm consistently wavering between IDs for them of simple quartz, moonstone (I'm just about 20 minutes away from Wausau, a locality known for a pretty variety of moonstone), and now have added a few other feldspar options to my list. If I could see any one of those stones in a natural cleaned specimen, it would probably help me but instead I must currently rely on internet and book photos, which quite frankly can all look exactly the same.

And even after the complaint about my billion-cajillion tons of unknown and probably leaverite materials, I accepted a wheelbarrow full of what appears to be HUGE chunks of petrified wood. If it's not petrified wood, it sure is the best imitation ever of a tree, bark and growth rings and all, just in agate-ish colors. About to post a quick pic of that in a new thread once I get my very tired and bruised butt up to go outside to take the photo.

Also, to get back on the topic specimen (sorry, I'm a rambler), I totally agree with the idea that it's not really worth potentially ruining to test... I really like the little thing and it's already in a place of honor in my box of "Itty Bitty Pretties" so that's good for me.

 

[Eu_citzen]

Set up? I'm basically using a dremel and toothpicks wrapped with plumbers tape. (glued in place)
cutting/grinding paste I do myself with silicon carbide (SiC) and Vaseline. Or something similar similar to vaseline.

Mind you, I'm trying to teach myself to carve to! Still in the beginning of that project.
If you really decide to try it, keep a bucket full of patience at hand. Expect the first couple of tries to do bad.
And give me a holler if you need some practising material, I suggest something "soft".

Quartz is pretty easy to separate from Feldspar. Quartz has horizontal striations on its crystals.
Google pictures: "striation in quartz", looks like thin lines on the crystal.

The crystal shape looks very different to, but that is more difficult to describe.
Instead try this link for quartz:
Crystal Form of Quartz

That with the books is not so easy, they often use top-notch specimens for reference pictures.
Not exactly what you get to see every day. That was a mayor problem for me to.