Stumped and Impatient

[iszy_suede]

Hi, just joined, I'm a beginning student in cut gems, though I've worked (ok, more played) in raw stones for a few years. I recently won an auction of over 400 stones (mostly minor bits, figured good for a beginner), and while I'm having no problem identifying most of them, I have found one oddball that has thrown me for a loop.

I'm also out of my home area at the moment. So I don't have my books or anything beyond a loupe. I'll be able to go back to a museum and do tests in maybe a couple of weeks, but I don't think my curiosity can wait that long!

So, to the eye, the stone appears to be a medium dark pink going on red. It is fairly included but not so cloudy as to be opaque. It was in a container with 3 other stones I have concluded are very low grade small rubies (cloudy to the point of nearly totally opaque, bad color, and pass a scratch test up to a 9 on the mohs' scale).

Scratch test puts it between a 6 and a 7 on the mohs' scale, and what has me most confused is, while not visible to the eye, once put under the loupe the color becomes exceedingly splotchy. It looks like TINY pale blue and deep pink leopard print!

I figured this might be caused by diffusion, but I've never looked at a diffused stone before, and what I'm finding online says that diffusion is mostly only used on corundum, and with a hardness less than 7, it can't be a corundum.

So. Yes. Confused. Any thoughts?

 

[Enerchi]

pictures? louped pictures?

 

[chrono]

The effects of diffusion will be even colouration viewed through a loupe. Sounds like it is possibly clarity enhanced with some sort of coloured resin.

 

[Lee Little]

I would take a guess at it being dyed quartz. Best regards, Lee

 

[iszy_suede]

OK, I'm not a photographer, but this is the best I could do. Still another week, probably, until I get access to anything helpful in the equipment department. Hopefully you can see how it's kind of tiny clear/blue and pink spotty - that's not just pixelation.

 

[iszy_suede]

Oh, and as I'm still working through the batch, I've found 4 more, just glancing at them I had assumed garnet, but again, under the loop the color is very streaky/stripey alternating dark pinky-red and clearish-blue. Read the entire chapter on common methods of altering the color of gemstones in my text book, but it doesn't mention any causing a streaky/striped appearance under a loupe.

To add to the confusion, while the original stone would not scratch quartz crystal, at all, these new 4, all scratch quartz very easily.

 

[Jeweljunke]

Sunstone? But sunstone is a softer stone.

 

[Jeweljunke]

Kinda looks like this stone http://www.oregon-sunstone.com/.docs/record_id/10121/pg/10087

 

[Lee Little]

Oh, and as I'm still working through the batch, I've found 4 more, just glancing at them I had assumed garnet, but again, under the loop the color is very streaky/stripey alternating dark pinky-red and clearish-blue. Read the entire chapter on common methods of altering the color of gemstones in my text book, but it doesn't mention any causing a streaky/striped appearance under a loupe.

To add to the confusion, while the original stone would not scratch quartz crystal, at all, these new 4, all scratch quartz very easily.

The streaky colors doesn't ring a bell but if they look like Garnets and scratch Quartz they are likely Spinel.

 

[iszy_suede]

Yeah, Sunstone is too low on the mohs' scale, and they are decidedly pinkish in hue, not orange.

Here, I'll try and take a picture again of one of the other 4, the biggest one. I know I don't have the right equipment yet; but you should be able to see the stripes in this one pretty easily.

 

[chrono]

Looks like colour zoning to me which happens to a variety of gemstone types.

 

[iszy_suede]

Thanks, SO MUCH! I guess I thought color zoning was much more common in larger bands, like bicolor Tourmaline - I never found anything before that suggested it could be so.. . "stripey"

And that first pic looks almost identical to the new 4, same color tone, same kind of striping. At least I feel better now that it's not some kind of botched attempt at color alterations, or fakes. The more I examine my stash the more I'm pretty sure what I have is a beginner gem cutters early work. There's a lot of odd sizes, close-but-not-quite sets, and little off details (like girdle being thicker on one side than the other, small chips on the edge of the crown) - but, still. It's a good lot for a student to work with, and I still got nearly 500 specimens for $60, so I guess I really can't complain.

 

[Lee Little]

That is a great study parcel, really cheap too.
That is indeed natural color banding. When they are in straight lines like that it means they are very likely natural origin. Best regards, Lee

 

[Jeweljunke]

Kinda looks like this stone?: http://www.ebay.com/itm/0-95ct-Very...769?pt=LH_DefaultDomain_0&hash=item5639c41b21

 

[iszy_suede]

The color zoning is the same, but these are much darker-purple/red with a kind of magenta pink tinge to them.

If I use the GIA color gemstone grading chart. PR/RP, with strong saturation and about an 8-ish (no lighter than 7, def no darker than 9)

 

[Jeweljunke]

Oh well. It is fun guessing. You HAVE to tell us what it is when you find out for sure!