Fluorescent Mineral Specimens Under Shortwave and Longwave Ultraviolet Light

Polman Minerals
Fine Fluorescent Mineral Specimens
and Ultraviolet Lamps

Potter-Cramer Mine Showcase

 

 

The Potter-Cramer Mine is located southwest of Wickenburg, in the Belmont Mountains, Maricopa County, Arizona.  The mine was originally developed prior to the 1920s, and has produced lead, silver and gold.  The earliest record of mining operations with the Bureau of Mines was in 1942, when the mine was called the Lost Spaniard.  The mine was then operated by the Vulture Mining Company.  Records indicate that only a small amount of ore was processed due to the troubles the owners had with labor.

In 1967, Dr. Sidney A. Williams, a Phelps Dodge research geologist, was collecting information on the geology of the Potter-Cramer Mine.  While studying the geology, Dr. Williams collected several specimens.  One of the specimens collected, contained a new mineral species.  The new mineral was called wickenburgite, and was approved by the International Mineralogical Association in 1968.  Since the Potter-Cramer Mine was now the Type Locality for wickenburgite, samples were sent to the Smithsonian Institution for their vast collection. 

Wickenburgite is a rare lead aluminum calcium silicate hydroxide Pb3Al2CaSi10O24(OH)6.  Wickenburgite is usually white, colorless or in rare instances pink.  It is well crystallized to granular, with hexagonal crystals ranging from 0.2 to 1.5 mm across.  Most wickenburgite is found as micro crystals in spongy aggregates.  The host rock for the wickenburgite is a rhyolite breccia.  The wickenburgite is an oxide zone mineral, found in veins and fractures within the host rock.  These veins and fractures originally contained deposits of galena and sphalerite.  Gangue minerals present in these veins are mostly quartz and fluorite.  Some other minerals found within these oxide zones include willemite, phoenicochroite, mimetite, pyromorphite, galena, chalcedony, cerussite and crocoite among others.  Wickenburgite is the most abundant mineral present at the mine, and was among the last to crystallize.

Several minerals have been found to fluoresce at the Potter-Cramer Mine.  These minerals include wickenburgite, willemite, fluorite, chalcedony and cerussite.  Wickenburgite fluoresces best under shortwave ultraviolet light, with a response ranging from Bazooka bubble gum pink (for those who are old enough to remember Bazooka bubble gum) to deep crimson red.  Willemite fluoresces best under shortwave ultraviolet light, with a response ranging from creamy yellow/white to green.  The willemite is also phosphorescent.  Fluorite fluoresces under both longwave and shortwave ultraviolet light, with longwave providing the best result.  The fluorescent response for the fluorite is typical europium activated purple.  The fluorescent chalcedony was only identified after I claimed the mine in 2002.  Manny Robbins had described it in his second book as the unknown mineral that fluoresced “cornflower blue.”  The chalcedony does fluoresce a beautiful cornflower blue under shortwave ultraviolet light, but is not as common as the wickenburgite, willemite and fluorite.  The least common fluorescent mineral found so far at the Potter-Cramer Mine is cerussite.  In some specimens, small amounts of cerussite will fluoresce yellow under longwave ultraviolet light.  I should mention that some fluorescent caliche can be found at the Potter-Cramer Mine that fluoresces yellow/orange as well, so it’s best not to get the two minerals confused.

I first collected at the Potter-Cramer Mine in 1986, when I moved to Arizona.  On the dumps I did find specimens that contained wickenburgite, willemite and fluorite.  These were very attractive three color specimens.  I kept some for my own collection, and offered others for sale through Polman Minerals.  All in all, I may have collected at the mine five or six times in the late 1980s and early 1990s.  In 2002, I found out that the Potter-Cramer Mine was open to claim.  I later went out to the mine, staked my claim, filed the proper paperwork with the Bureau of Land Management and became the mine owner a month or so later.

The entrance to the mine is a vertical shaft that is approximately 60 feet deep.  At the bottom of the mine there is a drift which leads to a big open stope.  At the far end of the stope, the ore was gravity fed down a 5-foot wooden ore shoot.  From there an ore cart ran on rail to an exit which has since been sealed off.  Unfortunately for me, the ore cars had been removed early in the mine history, but the rail was still left in place.

I did some small-scale mining in 2002, when getting/using explosives was still relatively easy.  Working a small mineralized seam at the surface near the vertical shaft, we drilled and blasted the rock.  I obtained several flats of decent specimens for sale, but did not mine further once the strict explosives laws took affect shortly thereafter.

In October of 2016, I decided it was time to do some much larger scale mining for specimens at the Potter-Cramer Mine.  With the help of four good friends, David Giebelstein, Mike Sawicki, Nate Johnson and Phil Smith, we spent the weekend of October 29, 2016 mining.  Without explosives, we decided to just use a rock drill,  jackhammer and expansion grout to work the mineralized zone near the vertical shaft of the mine. The rock was hard, and following the mineralized vein was difficult.  After a full weekend of work, we moved a lot of rock, and managed to collect some of the finest specimens of wickenburgite that have ever been produced from the mine.  Below I have provided a few pictures of the mine, and mining operations.

Potter-Cramer Mine
Vertical shaft at the Potter-Cramer Mine

A great photograph of the Potter-Cramer Mine
 taken by my good friend Al Liebetrau in 2004. 

The vertical shaft at the Potter-Cramer Mine. 
The photograph was taken by Mike Sawicki
on 10/29/16

 

 

Drift in the Potter-Cramer Mine
Vein of galena in the Potter-Cramer Mine

Here is the drift leading to the main open
stope.  The photograph was taken in 2003.

A photograph taken in 2016, showing a
nice vein of galena in the main open stope.

 

 

George on the second level of the Potter-Cramer Mine
The vertical shaft at the Potter-Cramer Mine

Here I am next to the ore shoot on
the second level of the mine.  Photograph
taken on 10/29/16 by Phil Smith.

Here is a view of the vertical shaft.  It takes a
40-foot and a 20-foot ladder to reach the bottom of the shaft.  The photograph was taken on 10/29/16.

 

 

Mining at the Potter-Cramer Mine
Mining at the Potter-Cramer Mine

Nate Johnson (left) and me, drilling the rhyolite breccia to get access to the mineralized vein
beneath.  The photograph was taken by
Mike Sawicki on 10/29/16.

From left to right, my good friends, David
Giebelstein, Nate Johnson, Mike Sawicki and
Phil Smith.  All five of us were exhausted after
a full weekend of mining.  The photograph
was taken on 10/29/16.

 

 

 

 

The specimens offered for sale below were photographed using a 36-watt shortwave ultraviolet lamp.  I did not use longwave ultraviolet light during photography because it tended to make the fluorescent purple fluorite over-power the wickenburgite.  In most specimens, you still can see the fluorescent fluorite present, even under shortwave ultraviolet light only.  Since some of the rhyolite host rock was brecciated, some of the specimens may tend to be a bit crumbly and shed slightly.  Prices for the most part are based on the amount of the rarer wickenburgite present in the specimen.  However, some specimens are very aesthetic when they contain three or four different fluorescent minerals, and are also priced accordingly.

To order a specimen from this Showcase, just email or call with the number you wish to purchase.    When a specimen is sold it will be marked SOLD in red.  When new specimens are posted, sold specimens will be deleted, and new specimens added in their place.

 

For quick email access to purchase a specimen, you may click here.

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-100w

PC-100s

 

 

Number: PC-100 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 7.5 x 3.5 x 2.5-inches    Notes:

Price:  $600.00  SOLD

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-101w

PC-101s

 

 

Number: PC-101 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 7 x 5 x 2.5-inches    Notes:
Ex. George V. Polman Collection #2563.
Price:  $500.00  SOLD

 

 

White Light

Shortwave Ultraviolet

PC-102w

PC-102s

 

 

Number: PC-102 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 6 x 4 x 2.5-inches    Notes:

Price:  $400.00 

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-103w

PC-103s

 

 

Number: PC-103 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 5 x 3.5 x 3-inches    Notes:

Price:  $400.00  SOLD

 

 

White Light

Shortwave Ultraviolet

PC-104w

PC-104s

 

 

Number: PC-104 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 12 x 7 x 3-inches    Notes:

Price:  $800.00 

 

 

White Light

Shortwave Ultraviolet

PC-105w

PC-105s

 

 

Number: PC-105 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 5.5 x 4 x 4-inches    Notes:

Price:  $500.00 

 

 

White Light

Shortwave Ultraviolet

PC-106w

PC-106s

 

 

Number: PC-106 
Name & Location: Wickenburgite, Willemite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 7 x 5 x 5-inches    Notes:

Price:  $500.00 

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-107w

PC-107s

 

 

Number: PC-107 
Name & Location: Wickenburgite, Willemite, Fluorite, Chalcedony, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 5 x 4 x 2.5-inches    Notes:
Specimen contains rare “cornflower blue” chalcedony.
Price:  $400.00  SOLD 

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-108w

PC-108s

 

 

Number: PC-108 
Name & Location: Wickenburgite, Willemite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 5 x 3 x 2-inches    Notes:

Price:  $350.00  SOLD 

 

 

White Light

Shortwave Ultraviolet

PC-109w

PC-109s

 

 

Number: PC-109 
Name & Location: Wickenburgite, Willemite, Fluorite, Chalcedony, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 4.5 x 3 x 2-inches    Notes:
Specimen contains rare “cornflower blue” chalcedony.
Price:  $300.00 

 

 

White Light

Shortwave Ultraviolet

PC-110w

PC-110s

 

 

Number: PC-110 
Name & Location: Wickenburgite, Willemite, Fluorite, Cerussite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 3.5 x 3.5 x 1.5-inches    Notes:
Specimen contains rare cerussite not seen in photograph.
Price:  $300.00 

 

 

White Light

Shortwave Ultraviolet

PC-111w

PC-111s

 

 

Number: PC-111 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 5.5 x 3.5 x 3-inches    Notes:

Price:  $500.00 

 

 

White Light

Shortwave Ultraviolet

PC-112w

PC-112s

 

 

Number: PC-112 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 4.5 x 3 x 1.5-inches    Notes:

Price:  $350.00

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-113w

PC-113s

 

 

Number: PC-113 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 7 x 4 x 2.5-inches    Notes:

Price:  $600.00  SOLD

 

 

White Light

Shortwave Ultraviolet

PC-114w

PC-114s

 

 

Number: PC-114 
Name & Location: Wickenburgite, Willemite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 6.5 x 4 x 2-inches    Notes:

Price:  $350.00

 

 

White Light

Shortwave Ultraviolet

PC-115w

PC-115s

 

 

Number: PC-115 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 7 x 7 x 3.5-inches    Notes:

Price:  $500.00

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-116w

PC-116s

 

 

Number: PC-116 
Name & Location: Wickenburgite, Willemite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 3.5 x 3 x 2-inches    Notes:

Price:  $350.00  SOLD

 

 

White Light

Shortwave Ultraviolet

PC-117w

PC-117s

 

 

Number: PC-117 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 7 x 4.5 x 2-inches    Notes:

Price:  $500.00

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-118w

PC-118s

 

 

Number: PC-118 
Name & Location: Wickenburgite, Willemite, Fluorite, Chalcedony, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 4.5 x 3.5 x 2.5-inches    Notes:
Specimen contains rare “cornflower blue” chalcedony.
Price:  $300.00  SOLD

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-119w

PC-119s

 

 

Number: PC-119 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 3.5 x 2.5 x 1.5-inches    Notes:

Price:  $150.00  SOLD

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-120w

PC-120s

 

 

Number: PC-120 
Name & Location: Wickenburgite, Willemite, Fluorite, Chalcedony, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 3.5 x 2.5 x 1.5-inches    Notes:
Specimen contains rare “cornflower blue” chalcedony.
Price:  $150.00  SOLD

 

 

White Light

Shortwave Ultraviolet

PC-121w

PC-121s

 

 

Number: PC-121 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 3.5 x 3 x 1.5-inches    Notes:

Price:  $200.00

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-122w

PC-122s

 

 

Number: PC-122 
Name & Location: Wickenburgite, Willemite, Fluorite, Chalcedony, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 6 x 3.5 x 2.5-inches    Notes:
Specimen contains rare “cornflower blue” chalcedony.
Price:  $450.00  SOLD

 

 

White Light

Shortwave Ultraviolet

PC-123w

PC-123s

 

 

Number: PC-123 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 5.5 x 5.5 x 3-inches    Notes:

Price:  $400.00

 

 

White Light

Shortwave Ultraviolet

PC-124w

PC-124s

 

 

Number: PC-124 
Name & Location: Wickenburgite, Willemite,  Potter-Cramer Mine, Maricopa County, Arizona.
Size: 7 x 4 x 4-inches    Notes:

Price:  $500.00

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-125w

PC-125s

 

 

Number: PC-125 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 4.5 x 2.5 x 1.5-inches    Notes:

Price:  $300.00  SOLD

 

 

White Light

Shortwave Ultraviolet

PC-126w

PC-126s

 

 

Number: PC-126 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 3.5 x 3.5 x 2-inches    Notes:

Price:  $200.00

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-127w

PC-127s

 

 

Number: PC-127 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 3.5 x 2 x 1.5-inches    Notes:

Price:  $150.00  SOLD

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-128w

PC-128s

 

 

Number: PC-128 
Name & Location: Wickenburgite, Willemite, Fluorite, Cerussite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 2.75 x 2.5 x 1.5-inches    Notes:
Specimen contains rare cerussite not seen in photograph.
Price:  $150.00  SOLD

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-129w

PC-129s

 

 

Number: PC-129 
Name & Location: Wickenburgite, Chalcedony, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 2 x 2 x .75-inches    Notes:
Specimen contains rare “cornflower blue” chalcedony.
Price:  $50.00  SOLD

 

 

White Light

Shortwave Ultraviolet

PC-130w

PC-130s

 

 

Number: PC-130 
Name & Location: Wickenburgite, Willemite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 3 x 2.5 x 2-inches    Notes:

Price:  $75.00

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-131w

PC-131s

 

 

Number: PC-131 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 3 x 3 x 1.5-inches    Notes:

Price:  $75.00  SOLD

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-132w

PC-132s

 

 

Number: PC-132 
Name & Location: Wickenburgite, Chalcedony, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 4 x 3 x 2-inches    Notes:
Specimen contains rare “cornflower blue” chalcedony.
Price:  $200.00  SOLD

 

 

White Light

Shortwave Ultraviolet

PC-133w

PC-133s

 

 

Number: PC-133 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 4 x 2.5 x 1.5-inches    Notes:

Price:  $65.00

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-134w

PC-134s

 

 

Number: PC-134 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 2.5 x 2.5 x 1.5-inches    Notes:

Price:  $75.00  SOLD

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-135w

PC-135s

 

 

Number: PC-135 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 4.5 x 4 x 3-inches    Notes:

Price:  $300.00  SOLD

 

 

White Light

Shortwave Ultraviolet

PC-136w

PC-136s

 

 

Number: PC-136 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 3.5 x 3 x 2.5-inches    Notes:

Price:  $150.00

 

 

White Light

Shortwave Ultraviolet

PC-137w

PC-137s

 

 

Number: PC-137 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 4 x 2 x 2-inches    Notes:

Price:  $100.00

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-138w

PC-138s

 

 

Number: PC-138 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 3 x 2.5 x 1-inches    Notes:

Price:  $100.00  SOLD

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-139w

PC-139s

 

 

Number: PC-139 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 3.5 x 2 x 2-inches    Notes:

Price:  $200.00  SOLD

 

 

White Light

Shortwave Ultraviolet

PC-140w

PC-140s

 

 

Number: PC-140 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 10 x 5 x 5-inches    Notes:

Price:  $400.00

 

 

White Light

Shortwave Ultraviolet

PC-141w

PC-141s

 

 

Number: PC-141 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 5 x 4.5 x 4-inches    Notes:

Price:  $500.00

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-142w

PC-142s

 

 

Number: PC-142 
Name & Location: Wickenburgite, Chalcedony, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 4.5 x 3.5 x 2-inches    Notes:
Specimen contains rare “cornflower blue” chalcedony.
Price:  $300.00  SOLD

 

 

White Light 

Shortwave Ultraviolet 

PC-143w

PC-143s

 

 

Number: PC-143 
Name & Location: Wickenburgite, Willemite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 4.5 x 3.5 x 2.5-inches    Notes:

Price:  $400.00 

 

 

White Light

Shortwave Ultraviolet

PC-144w

PC-144s

 

 

Number: PC-144 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 5 x 4.5 x 3-inches    Notes:

Price:  $500.00

 

 

White Light  SOLD

Shortwave Ultraviolet  SOLD

PC-145w

PC-145s

 

 

Number: PC-145 
Name & Location: Wickenburgite, Willemite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 5 x 3 x 3-inches    Notes:

Price:  $400.00  SOLD

 

 

White Light

Shortwave Ultraviolet

PC-146w

PC-146s

 

 

Number: PC-146 
Name & Location: Wickenburgite, Willemite, Fluorite, Potter-Cramer Mine, Maricopa County, Arizona.
Size: 9 x 5 x 5-inches    Notes:

Price:  $500.00

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