CompuServe Thread

selenites

8 messages in this thread
#121563From: Larissa A. McCutcheFeb 19, 1994 7:42 PM
Hi Bill, When I was up at the mines near here, the head geologist showed me some eucryptite. The whole piece seemed to be a light pink, yet only portions showed the bright pink. As for your other piece, it sounds a bit like my piece of apatite. I found my deep blue-green apatite in the same area as some lepidolite and other basic pegmatite stuff. The only real difference is the fluorescence. I've been told that this is apatite, hmmm… maybe I should check. I'll try on Monday. This is also an amorphous piece, so I can't say anything as to the cleavage. L.McC.
#121789From: Bill Webb /CAFeb 21, 1994 6:07 PM
Larissa.. Thanks for the suggestion. I went back to the specimen and began to wonder about my analysis of the cleavages, especially after checking with Northrup, Minerals of New Mexico, and recalling that apatite(s) haven't much going for them when it comes to cleavage. Northrup describes dark blue-green apatite from the Harding mine! So, I wonder about the cleavage and still puzzled about all the right angle ?fractures? , but am now leaning towards apatite and interpreting the ?fractures? as not cleavages but perhaps an artifact of stresses in the rock.. or something of the kind. These minute cracks run parallel to the axis of the prisms, are uniformly 2-3 mm wide. We'll see what Doug has to say about this. He'd love the bright golden yellow fluorescence (SW).
#121852From: Larissa A. McCutcheFeb 22, 1994 8:45 AM
Hi Bill, I checked my apatites, no fluorescence. One of my rock books mentions that apatite occasionally possesses a strong yellow fluorescence… L.McC.
#121937From: Doug MitchellFeb 23, 1994 12:00 AM
Hi, Larissa– I failed to note your mention of apatite, which certainly fits the hardness better, and which does indeed tend to fluoresce yellow more often than any other color in my experience. Once in a while apatite gives a bright blue fluorescence like the common fluorite response; I have been looking for one of those. –Doug
#121938From: Doug MitchellFeb 23, 1994 12:00 AM
Hi, Bill– Apatite being known at the Harding mine, go for it! It fits the hardness and fluorescence. Perhaps your 90 degree cleavages are crystal faces? A termination would often be a flat face at 90 degrees to one of the prism faces. I do not know about your "stress markings" – phantoms, maybe? A piece to look at would be welcome and might clinch the ID, provided you do not break the specimen up trying to get it! If you decide to chance it, I am at 12831 N Stratford Dr #150, Oklahoma City, OK 73120. According to Gemstone & Mineral Data Book (Sinkankas) useful liquids are hexane (.66), heptane (.68), isopropanol, methanol, or ethanol (.79 – surely these are 200 proof), acetone (.79 again; nail polish has it, but again maybe not concentrated enough), kerosene (.80-.84), amyl alcohol (.81), mineral oil (~.84), toluene (.867; do not become a glue-sniffer!), amyl acetate (banana oil), ethyl valerate(.88), and oops, there is another page so I am not going to type them all, just some one might find at home: water (.998) diethylene glycol (antifreeze) or salt water 1.12, glycerine (1.26), and carbon tetrachloride (1.541). The rest tend to be like cadmium borotungstate, diiodomethane, and other goodies.
#122499From: Bill Webb /CAFeb 28, 1994 2:01 AM
Doug.. the handy ones are probably the easiest to come by.. and the most useful. There are probably very few stones that would float on water, or anything with less than 1.00 SG. So how are those lightweights used? (Besides sniffing). I am sticking with apatite, and the marks are like hairline fractures, all running parallel with the xl axis, and reach the surface. I don't think phantoms. You'll see. I am still waiting to send you several specimens once I re-visit some sites and can get better stuff. Still no UV lamp has come from Fl. Minerals in San Gabriel. Strange outfit. Bill
#122582From: Guy HammerFeb 28, 1994 7:52 PM
Bill– > There are probably very few stones that would float on water, or anything > with less than 1.00 SG. I'll collect some pumice specimens for you next chance I get. <G> –Guy /OR
#122609From: Doug MitchellFeb 28, 1994 10:23 PM
Hi, Bill– It must have been late when I started typing that list – the fact those early entries in the list were lighter than water escaped me until I had already typed them. It turns out there is another table of liquids used with minerals which I had confused this one with. The only ones I would expect to find in a kitchen or drugstore are salt water (which will isolate amber from other stuff) and carbon tetrachloride, which might help isolate such popular minerals as oxammite, but not much else. The rest are as commonplace as tetrabromoethane and thallium silver nitrate, except mercury, handy for identifying platinum nuggets if you happen to pass through Wickenburg :). I do not rely on UVP to be any faster replacing your damaged UV lamp than they were in supplying it originally – the market is so small, I imagine they may wait for a certain number of orders before initiating a production run, which might be needed to produce whatever parts need replacing in yours. –Doug