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!

Three Rock Hounding Trips to Lake George, CO in October #Onegite #Goethite #Amazonite #Rockhounding #Rocky Mountains

Snow beginning to pile up on Pikes Peak

As another rock hounding season in the Colorado Rockies comes to a close, I wonder if I will be able to get out there again, or is this it for the season?  Mother Nature has been telling me no as of late, but you never can tell.   Bob, my digging partner, and I have gone out a couple times during the month of October and neither of us can recall stopping this early in the season due to cold and snow.  Last month we decided to go back to one of our more productive sites but we’ve dug it so much it’s hard to figure out where to go next.  I decided to work a gully which I usually avoid, thinking it is just a collecting area for broken float crystals.  When I saw a couple of nearly complete well-formed microcline crystals I decided to give it a go.  Visually sorting the wheat (crystals from a nearby undisturbed pegmatite) from the chaff (broken float crystals from a nearby dig) is a learned skill. To my surprise there was a pegmatite only inches below the surface.  The peg was shedding microcline.  While a pegmatite with microcline is not too exciting I was hoping for a concealed crystal pocket with something better.  

One of the larger crystals from this small pocket

As I dug a little deeper into the pegmatite the microcline turned bluish green (amazonite), but was still not producing well-formed crystals.  On I went following the blue sign and sure enough I did manage to hit a small pocket.  The size of these amazonite crystals wasn’t very big but at least the color was above average.  I continued in the old water run following the pegmatite and blue sign.  Soon quartz started becoming more prevalent and I started getting a little excited.  I shoved a fairly large rock aside and underneath were a number of quartz crystals--even a combination of amazonite and quartz.  Unfortunately the quartz was layered with iron/goethite and not very appealing. The size of the combos was also underwhelming, but at least it was something.  As I continued to dig 

Quartz with goethite overgrowth

up the hill I hit a very large amazonite crystal, nearly the size of my fist.  I got excited enough to call Bob over, but the curse of calling my digging partner Bob over to see what I had found manifested itself once again.  The peg ended and the crystals dried up.  We joke about this phenomenon, so much so that I rarely call Bob over unless I’m really into something good.  Oh well.  I took about 75 crystals home from this spot but I'll be surprised if 10% of them are worth keeping.  Too much damage and too much iron coating.  Quite often shallow digs, suffer more damage than the deeper larger pockets infused with protective clays.  The iron coating seems to be happening more often than not on this part of the hill we've been digging.

Next visit. I prospected an adjoining hill to our successes of last year and found some old digs, but not much sign on the surface.  Even the old digging piles seemed nearly devoid of quartz.  I decided to prospect a slight spine running up the hill where others had dug, and tried to stay out of the run-down material from previous diggers.  After digging a bit I found a fairly nice phantom crystal ( a smoky crystal hooded in clear quartz), but determined it had eroded out of a pocket already dug up the hill from me. I decided to hop over the previous digs

Phantom quartz with prospector's thumb

and continue along the spine guiding me up the hill. Without much quartz sign I decided to dig anyways.  It reminded me of my late mentor Ray B.  Ray said that in some places at Lake George, all you have to do is throw your pick up in the air and start digging where it lands.  Might as well give that method a try I guess nothing else was working.  It was near the end of the day and I had invested some time and energy into the dig I was working on so I continued despite it's lean offerings.  Bob stopped by, bemoaning his lack of success and checked what I was up to.  I felt a little embarrassed showing him what I was digging in but at least there were some small quartz crystals. Bob decided to dig up the hill from me.  Soon we were both finding some small quartz crystals.  At the end of the day we decided this area merited further prospecting.

Third attempt for the month.  The next outing, was over a week later due to poor weather and other complications.  We headed straight for our new area up at Lake George to do some prospecting.  I found the pegmatite I was working on the last trip, but it continued to only yield small float quartz crystals, similar to our last visit.  Bob found a pegmatite nearby, and started finding some more impressive specimens.  Unfortunately nearly 80% of what Bob was finding was badly damaged.  Still, he did find some very impressive goethite, onegite, and a couple double terminated quartz crystals. I think he even scored some small fluorites.  I continued to slog my way along my pegmatite finding only small iron/goethite coated crystals.  After a bit the small quartz crystals I was finding seemed more frequent on the right than on my left.  I followed the crystals on my right and was soon pulling out more productive looking pegmatite (larger grained rock).  I decided I needed to stretch my legs and walked over to where Bob was digging.  Bob had an impressive pile of broken quartz crystals and microcline.  He did show me a very nice 3" double terminated smoky and remarked that he was also finding some goethite and fluorite.  I guess there was some hydrothermal activity on this hill at some point in time, that helped bring about the goethite and fluorite specimens. I remarked that Bob was doing better than me this day and he certainly had some keepers.  

A keeper for sure!

A good day is when we both find something to take home.  A really good day is when we find something good enough to put in our display cabinets at home.  Bob was having a really good day.  I returned to my pegmatite which was about a foot below the surface.  As I dug I noted an occasional weathered chunk of goethite.  All the nice goethite needles and sprays were worn down but I figured at least it was something to follow up the hill.  As I proceeded along the pegmatite, a softer area began to develop in the middle of the pegmatite.  I no sooner noted the change than I was pulling out goethite sprays.  These sprays were well defined.  I determined that this must have been where the floater goethite chunks I had found earlier originated.  I pulled out about 8 fist sized or smaller chunks of goethite and noted some had quartz crystals embedded in the goethite as well as a few very small fluorites.  I wasn’t competing with Bob’s finds but at least I would not go home empty handed.  Bob checked out my progress and decided I should have one of his onegites with goethite sprays.  Onegite as a mineral has been discredited but we use the term locally to define quartz with goethite inclusions.  Onegite was first discovered and named in Onega, Russia only to be later discredited as a separate mineral. Thanks Bob!  Sympathy onegite.  I’ll take it!  :-)   

A nice grouping of goethite on quartz peppered with onegite crystals

It’s been a slow year for both of us though not without some fun.   I hope we can get back to this area a time or two before winter shuts us out completely.  Who knows what we will find next on this crazy hill.