Rock Hounding At Collector's Edge--An Indoor Field Trip

Namibia amethyst group with odd termination

Rock hounding minerals in Colorado can run a bit far afield, especially when I set the rules. When it’s cold and icy outside a little shopping for deals at local rock emporiums helps pass the winter time.  I took a planned trip up to Denver and checked out Collector’s Edge (CE).  Now I’ve always understood Collector’s Edge to be higher end, an out of reach dealer for the regular collector, but who knows.  I went on a tour with a couple other Joes and was greeted at the door by Phil Perrson.  Phil has been working for CE for over a year and has a MS in geology.  We were welcomed into a foyer where to the left a number of fairly old brass microscopes, goniometers and other antique rock viewing instruments were on display.  I found their workmanship astonishing considering many of the instruments were made over 100 years ago.  From the museum display we went into the high end mineral area, and were overwhelmed by the proprietor (Bryan Lees') personal Colorado collection.  Everything was there that could be found in Colorado with a special emphasis on rhodochrosite from the Sweet Home Mine, barite from Stoneham, and smoky and amazonite combinations from the Pikes Peak Batholith. The showroom had wall-to-wall cases loaded with mineral specimens. Each mineral was carefully documented and aesthetically displayed.  After an hour or so of examining these specimens we moved on to the lab and prep area.  In the lab a number of large concretions from Mexico were being cut up for the brown barite crystals hidden inside.  There were also a number of brilliant yellow brucite specimens the cleaners were working on.  Lab workers were also working on a number of plumbogummite plates that I recalled from an article in the Mineral Record magazine. Plumbogummite is

Plumbogummite

pyromorphite crystal, whose terminations have pseudomorphed into beautiful light blue plumbogummite. I really liked saying the word plumbogummite, and much to the consternation of my traveling buddy I preferred to call it plumbogumbo.  I decided that despite CE’s prices I might have to get one.  I saw lots of chemicals, exhaust hoods and vacuum chambers, some epoxies with dyes, numerous saws and a number of friendly people. The workers seemed happy in their tasks, perhaps that was because Bryan Lees, the proprietor, was in China?  Next up was a staging room for the Tuscon Show.  I think there was at least a semi-truck of flats ready to go to Arizona in January. The Tuscon mineral show is the largest show of its kind.  We had reached the end of the building.  Thinking we were done I asked Phil if there were any less pricey plumbogummites to be had.  Phil said of course there are, after lunch we’ll go to the warehouse.  Warehouse… who knew?!

Lunch didn’t go by fast enough for me.  I wanted to get back to the warehouse. The warehouse is located about a block away from the main work area and offices.  They had a keystone (half-price) area where you can buy single crystals and another area with flats of minerals. I went immediately to the keystone area looking for a plumbogummite that I could afford.  I got a nice plumbogumbo for a good price and moved on to where my chums were looking through flats. I think there were well over 1000 flats of minerals.  My chums decided to split a flat as who needs a couple dozen fluorite even if you do trade/sell some.  I thought maybe I’m better off back at the keystone area. Then I noticed some of the flats said mixed minerals--Namibia.  Hmmm lots of different stuff in a flat, maybe I don't need to buy 20 of one thing.  Plenty to look at and maybe add to my collection.  Yea I can spring for one of those boxes. The problem with my collection is it’s all black and blue… I kid you not.  Too much blue amazonite and black smokys--not bruised minerals.  I think I looked through about 100 boxes of mixed minerals from Namibia.  Boxes ranged from 4 specimens (museum size) to 54 specimens (thumbnails).  Prices ranged from $50 to $500 a box depending on the mineral quality. I went for cabinet size pieces and got a flat with 18 specimens from Namibia.  There was some duplication but I didn’t mind that too much. I figured 3 of the specimens in the flat could pay for the entire box. 

Schorl with fluorite

Schorl is not my favorite mineral but when it’s combined with other things like fluorite I find it acceptable.  So I got schorl with fluorite, schorl with aquamarine and plain old schorl.  I also got stand-alone fluorites, a topaz, an aquamarine and a few oddities I have to figure out.  What fun!

    So where do I start with the flat?  First I divided everything up into known, and unknown specimens.  Instead of being lazy and asking folks on the internet for help on what different minerals were, I decided a cold Saturday afternoon was the perfect time to learn how to do a specific gravity (SG) test.  I also used a couple other techniques to see if I could figure out what some of these odd minerals were.  I read up a bit on minerals of Namibia at various web-sites to see what was possibly in my subset of unknown minerals.  The specific gravity test is pretty easy, just google John Betts for information.  I decided to do the specific gravity test on a few known minerals like quartz, fluorite and microcline to see if my technique was reliable enough.  I got SGs of 2.54 for microcline, 3.05 for fluorite, and 2.63 for quartz.  All within tolerance as far as I was concerned which is probably why I only got a B- in college chemistry.  See for info: https://www.engineeringtoolbox.com/minerals-specific-gravity-d_1644.html.  Time to check out those unknown minerals.   Oh-oh the unknown minerals are primarily mixed or on matrix.  So taking the specific gravity of a mixed mineral won’t work, I need solitary minerals for the SG test… oops.  Well, I did what I could and verified a couple fluorites, a topaz, and a couple cerrusite. The rest of my unknowns are either on matrix or have associated minerals with them.  I was hoping for some dioptase but alas, only green fluorite.  It was a fun time looking through the minerals at CE.  The people there were friendly, Phil was a great host.  The end result was I am now able to use the specific gravity test to identify a few more minerals.  I also added some colors to one of my display cabinets.  Hooray, my cabinets are healed, no longer black and blue!