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[Ryaly2dogs]

Taking a page from Jay's (Sandsave's) book, I went out, located some rough, and attempted to try to match his most excellent Dumortierite sphere he posted a few weeks back.  While I located a huge 35 lb. chunk to work with, it was a darker blue to start with, turned a beautiful deep midnite blue shortly after the first saw cuts, then oxidized to a blacker blue within a few hours.  Despite the setback, I proceeded forward thinking I could polish past the black and bring out the blue, but ultimately fell short.  Final score: nature 1, man 0.

Shown is my 4.7-inch diameter dumortierite sphere, the rough reportedly collected from Imperial Valley by someone in our Ventura rock club.  No light filters used to show its very dark blue to black color.  Not sure what the whitish inclusion is.  Maybe Steve Ivie or someone similar may know this?

[Felicia]

Dumortierite seems to come in orange and kind of a gray as well, from what I've seen. Can't tell if that's dumortierite on your sphere, though

[Felicia]

Dumortierite seems to come in orange and kind of a gray as well, from what I've seen. Can't tell if that's dumortierite on your sphere, though

[Felicia]

Either my phone or the site went nuts, jumped around, and posted twice.

[Ryaly2dogs]

The reason I shared this thread is for the embedded lesson vs. simply posting more progress on spheres, since this topic is WELL covered. 

The point is, sometimes the material we are working on changes in the process, and the user needs to be mindful of the possibility.  I am kicking myself for not having photos of the "before" which would have showed the original beautiful blue color (before it oxidized into more of a black) which would really have helped bring the message home.

Thanks all.

[irockhound]

Not sure on the inclusion.  The material however is familiar.  Dark Durmorierite also comes from down near the Blue Bird mine on the East side of the 95 North of Yuma.

[Felicia]

Haven't yet worked with dumortierite (so many stones). Is it common for some of it to oxidize like that? The other sphere stayed a lighter blue, does the location where found matter?

[irockhound]

Many different materials do make a difference from site to site.  Take Opal as an example certain sites have opal that inherently tends to absorb water causing a temporary change in the Fire, other sites like Northern Nevada where it you don't get in water fast enough the opal will lose water and shatter (talking short time like minutes) and finally sites where the opal is perfectly stable (as perfect as something with water in its makeup can be).

I wonder with your Durmortierite having a reaction to oxidizing if other changes could be made easily?  If it is that sensitive, I wonder if short term exposure to UV could trigger a lightening maybe a couple months in the sun?  Many purple and Blue agates are subject to UV color changes, some getting more intense and others losing the color to a gray color.

[Sandsave]

I must have lucked out. You don’t have pics of the rough. Maybe a cut or something I’d really like to see one for future reference. I know where I might be able to get more and a bit of knowledge might be useful

[Ryaly2dogs]

There are good questions being posed here.  Let me cut some new rough, photo that and compare against a photo of already cut rough to show a Before and After picture.  This is the first time this has happened to me so I am sort of learning by doing.  Stay tuned.  I am told this came from Imperial Valley.

[irockhound]

My mistake in the map location.  Been years since I was down there.  I looked back at the Blue Bird Kyanite mine and it is off the Ogilby Road which is a cutoff from the 78 south of Blythe in yes you got it Imperial Valley.

The pic is a cab from the material there, very dark.  I would have to go thru my buckets to see what the rough looked like.

[Ryaly2dogs]

I attached 3 photos.  First is a piece cut a few weeks back that had oxidized a bit and appears almost a flat black, and shown adjacent is a fired clay pot of the desired blue color for comparison.  Second shot is a freshly cut piece that is very dark blue (and darker than my memory recalled), but still lighter and bluer than the older cut.  Final photo is showing fresh cut on left, old cut on right, and clay pot in center.  Verdict is that this material from Imperial Valley is darker to begin with (see also Steve's pendent above), but appears to oxidize a bit more after the cut (sort of like rhodonite left out for awhile).  If you desire the lighter blue like's Jay's really nice sphere, use material from other than Imperial Valley.

Thanks Steve for putting a specific location to the rock, that is more information than I started with.

[ileney]

 I am confused about dumortierite. I bought a few slabs years ago. They were cheap, sort of looked like dusty lapis with a dusty dark tannish crust but polished up to look just like blue lapis to my eyes, except has some black sparkles in it (no idea what that is) instead of pyrite. Is it suddenly as valuable as the Lapis or equivalent color? And what are those dark sparkles anyway?

[irockhound]

Durmortierite never demands the prices of Lapis and Durmortierite  comes in a variety of qualities. Obviously the brighter the blue the more popular but in terms of pricing the best Durmortierite is a steal for the bang you can get from the material and is really under rated as a gem material.  It is as tough as jade at times.  The cab I cut I think I posted I dropped from 4 feet on concrete and it bounced off and sounded like you dropped a 50 cent piece no damage.  Another great stone that was under rated and cheap for the longest time was Citron Chrysoprase.  I think they thought little of it since these considered it a  much lower quality of Chrysoprase but I tell you if you get that great solid key lime color it stands with the best in my opinion.  All comes down to public perception.  The lowest grade of lapis people had a hard time giving away till the sundance catalog had an epiphany and re branded it "Denim Lapis" and it became a craze.

[ileney]

LOL “denim lapis.” I don’t like it. Thank you for the explanation about dumportierite. I was very surprised by how the Dumortierite slabs I have start out Rough looking dusty blue and when polished turn into a much nicer, darker blue.