Log InRegister
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat Articles
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsThe ElementsUsersBooks & MagazinesMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Michael Cox's Photo Gallery

219-Y8CGaildunningite, Quartz

Clear Creek claim, Goat Mountain, New Idria Mining District, Diablo Range, San Benito Co., California, USA

Field of View: 0.350 mm

Photograph by Michael F. Cox from a type specimen in the collection of Gail Dunning. Orange gaildunningite on quartz. Identification confirmed per methodology detailed in the "The Canadian Mineralogist," Vol. 57, pp. 295-310 (2019), DOI: 10.3749/canmin.1800080.

Photo taken with Orthoplan compound research microscope fitted with 22x Ultropak system, halogen 100W incident polarized light, Sony A7R full-frame CMOS camera tethered to PC via Remote Camera Control (Copyright 2012-2017 Sony Corporation), 200 stills at 0.5 sec. per still and ASA-50 exposure speed, stacked with Zerene Stacker (Build T2018-07-19-1515, July 19, 2018) and some retouching done with Zerene Stacker to remove dust and eliminate haze.
Photo ID: 958022     Uploaded by: Michael Cox   View Count: 33   Approval status: Public galleries    Type: Photo - 7360 x 4912 pixels (36.2 Mpix)

W74-07MRadtkeite, Opalite

McDermitt Mine, Opalite Mining District, Humboldt Co., Nevada, USA

Field of View: 0.43 mm

Posted with permission of Dr. John McCormack, collector, photographer, author. Figure 4, page 27, McCormack, John, 1997, December, Mercury sulf-halide minerals and crystalline phases, and experimental formation conditions, in the system Hg3S2Cl2-Hg3S2Br2-Hg3S2I2, PhD Thesis, University of Nevada, Reno, Nevada, 163 pp.

It is important that this photograph be added to the radtkeite gallery. There is significant material in the world mislabeled as radtkeite. Radtkeite is exceedingly rare and fine grained. Most specimens in the world today are probably terlinguacreekite after and coating kleinite. Radtkeite is extremely light sensitive. It rapidly turns grey. Material from the discovery is no longer readily available. All of the material came from a single boulder broken loose during mining and collected by Dr. McCormack, working in the open-pit mine as a geologist.

Dr. John McCormack, the discoverer, failed to find any additional material after years of searching. A research project started in 2014 under the direction of Gail Dunning, Sunnyvale, CA, has also, as of Sept. 2018, not uncovered any confirmed radtkeite.

If anyone has a sample confirmed by at least pxrd, please contact Michael Cox or Gail Dunning. It is almost guaranteed that any radtkeite in a collection is another Hg mineral, especially if it has retained its orange-yellow color. It is most likely terlinguacreekite after and/or coating kleinite. If hexagonal prismatic crystals are present, terlinguacreekite after kleinite is a certainty.

Please refer to the American Mineralogist, 1991, Volume 76, pages 1715-1721: Radtkeite, HgrSrClI, a new mineral from the McDermitt mercury deposit Humboldt County, Nevada, by John K. McCormack, Frank W. Dickson, and Maureen P. Leshendok: http://www.minsocam.org/ammin/AM76/AM76_1715.pdf

Thank you for reading.
Copyright: © John McCormack, University of Nevada, Reno, Nevada      Photo ID: 909478     Uploaded by: Michael Cox   View Count: 48   Approval status: Public galleries    Type: Photo - 6477 x 4971 pixels (32.2 Mpix)

E0M-3LCRadtkeite, Opalite

McDermitt Mine, Opalite Mining District, Humboldt Co., Nevada, USA

Field of View: 0.87 mm

Posted with permission of Dr. John McCormack, collector, photographer, author. Figure 4, page 27, McCormack, John, 1997, December, Mercury sulf-halide minerals and crystalline phases, and experimental formation conditions, in the system Hg3S2Cl2-Hg3S2Br2-Hg3S2I2, PhD Thesis, University of Nevada, Reno, Nevada, 163 pp.

It is important that this photograph be added to the radtkeite gallery. There is significant material in the world mislabeled as radtkeite. Radtkeite is exceedingly rare and fine grained. Most specimens in the world today are probably terlinguacreekite after and coating kleinite. Radtkeite is extremely light sensitive. It rapidly turns grey. Material from the discovery is no longer readily available. All of the material came from a single boulder broken loose during mining and collected by Dr. McCormack, working in the open-pit mine as a geologist.

Dr. John McCormack, the discoverer, failed to find any additional material after years of searching. A research project started in 2014 under the direction of Gail Dunning, Sunnyvale, CA, has also, as of Sept. 2018, not uncovered any confirmed radtkeite.

If anyone has a sample confirmed by at least pxrd, please contact Michael Cox or Gail Dunning. It is almost guaranteed that any radtkeite in a collection is another Hg mineral, especially if it has retained its orange-yellow color. It is most likely terlinguacreekite after and/or coating kleinite. If hexagonal prismatic crystals are present, terlinguacreekite after kleinite is a certainty.

Please refer to the American Mineralogist, 1991, Volume 76, pages 1715-1721: Radtkeite, HgrSrClI, a new mineral from the McDermitt mercury deposit Humboldt County, Nevada, by John K. McCormack, Frank W. Dickson, and Maureen P. Leshendok: http://www.minsocam.org/ammin/AM76/AM76_1715.pdf

Thank you for reading.
Copyright: © John McCormack, University of Nevada, Reno, Nevada      Photo ID: 909475     Uploaded by: Michael Cox   View Count: 27   Approval status: Public galleries    Type: Photo - 6459 x 4935 pixels (31.9 Mpix)

RVU-F2ACinnabar

New Almaden Mine, New Almaden, New Almaden Mining District, Santa Cruz Mts, Santa Clara Co., California, USA

Field of View: 38 cm
Weight: 30 lb

California Icons: cinnabar and a ginger-beer bottle from the New Almaden mines. The large piece of rough ore represents the earliest cinnabar (HgS) ore to be mined at New Almaden. The specimen was found in an location associated with mining in the 1850s. The smaller piece of rough represents the last significant ore body found in the District. It was recovered in 1989, from a large ore body accidentally uncovered during the construction of a building near the Guadalupe mine, about 6 miles NW of the New Almaden mine. The rounded piece of ore is a classic cinnabar placer nugget. It was collected from the area of the Deep Gulch placer deposit, at the south end of the village of New Almaden. The ginger-beer bottle is also from the mines, found on a hillside in the early 1970s. The mines shut down at the end of 1975, and most of the mining lands became part of the New Almaden Quicksilver County Park. Collecting is prohibited without a permit.

In the first decades of operation, the New Almaden mines burned large pieces of broken ore such as that pictured. Cinnabar is about 13.8% sulfur and 86.2% mercury. The mercury is easily driven off by heating the ore to high temperatures. Ore mined in the early days was loaded by hand into vertical shaft furnaces constructed of red brick with a fire brick lining. The ore was fired for several days to drive the mercury vapor out of the rock and into plaster-lined brick condensation chambers. The host rock is silica-carbonate rock, also called calc-silicate rock. It is essentially dolomite and magnesite with quartz. Lime often had to be added to the furnace charges, in order to provide enough oxygen to combine with the sulfur and liberate the mercury vapor.

As an interesting aside, the 19th-Century fire brick lining the furnaces was imported from the United Kingdom. Heatherknowe is the most common 19th-Century maker's stamp found on fire bricks at the site. Accompanying the bricks were quantities of ceramic bottles of Scottish beer, such as that pictured.

Collection of Michael Cox. Paul Schraub, of Santa Cruz, CA, was retained to take the photograph. Permission to publish freely with attribution.
Copyright: © Michael Cox and Paul Schraub Photography      Photo ID: 847838     Uploaded by: Michael Cox   View Count: 107   Approval status: Public galleries    Type: Photo - 6449 x 4261 pixels (27.5 Mpix)

PF8-63ATerlinguacreekite, Quartz

McDermitt Mine, Opalite Mining District, Humboldt Co., Nevada, USA

Field of View: 800 μm

Modified by CombineZP
Photo ID: 826495     Uploaded by: Michael Cox   View Count: 56   Approval status: Public galleries    Type: Photo - 1131 x 776 pixels (0.9 Mpix)

3AN-R2LQuartz

McDermitt Mine, Opalite Mining District, Humboldt Co., Nevada, USA

Field of View: 4600 μm
Largest Crystal Size: 2.8 mm

Close up of double-terminated penetrating quartz crystals, iron stained, coated with somewhat iridescent unidentified mineral. This is a close up of photo 4QH-8PD. The bright reflections on the face of a quartz crystal in the upper left quadrant are of unknown origin. Colorless shockingly bright and clear double-terminated quartz is common in the rocks of the open pit, but the crystals are typically microscopic to just a few mm. These crystals are unusually large, but, sadly, coated with opaque minerals.

The sample came from rock collected during a two year study of the open pit. Gail Dunning of Sunnyvale, CA provided most of the mineral identifications for new and uncommon mercury species. Material recovery by Michael and Charles Cox with Ted Hadley and some assistance from Joe Marty, Dellilah Sabba, and Ed Speck.

The photo was taken with a circa-1985 Leitz Orthoplan research compound polarizing microscope fitted with a Leitz Ultropak incident light coaxial illumination system. The incident light is plane polarized 100W halogen.
Photo ID: 826432     Uploaded by: Michael Cox   View Count: 50   Approval status: Public galleries    Type: Photo - 4800 x 3200 pixels (15.4 Mpix)

4QH-8PDQuartz, Cinnabar

McDermitt Mine, Opalite Mining District, Humboldt Co., Nevada, USA

Field of View: 21 mm
Largest Crystal Size: 2.5 mm

Iron-stained double-terminated quartz crystals. A small patch of cinnabar is at the lower right. The quartz crystals are coated with a white slightly iridescent mineral that is unidentified. Taken with a Canon MP-E 65mm f/2.8 1-5x Macro mounted to a Sony A7R digital camera. Illumination using a 100W halogen dual-head fiber-optic illuminator. 50 images stacked using CombineZP. Adjusted for color, brightness, contrast, and clarity using Microsoft Photo.
Photo ID: 826363     Uploaded by: Michael Cox   View Count: 44   Approval status: Public galleries    Type: Photo - 4661 x 3146 pixels (14.7 Mpix)

1EM-LX4Schuetteite, Cinnabar, Quartz (Var: Chalcedony), Clays

McDermitt Mine, Opalite Mining District, Humboldt Co., Nevada, USA

Dimensions: 3.5 feet x 3.5 feet x 2 feet
Field of View: 2.5 feet
Weight: 700 lb

Photo taken by Mike Cox during geological examinations of the McDermitt open pit mine. Supergene schuetteite "blooms" surrounding dusty but rich cinnabar on the southeast face of a boulder of Miocene silicified tuffaceous sediments containing cinnabar, corderoite, gypsum, pyrite, and supergene clay minerals. These identifications are based on visual examination in the field and under the polarizing microscope back in the lab. The cinnabar and corderoite turns dark grey in sunlight. A small patch was chipped away to reveal the bright-red ore. Schuetteite blooms are surficial and somewhat seasonal. They seem to occur where the cinnabar and corderoite is soft and dusty (not highly silicified.) Cox has noticed that schuetteite blooms are thickest and most pronounced where gypsum and/or alunite occurs with concentrated but dusty colloidal cinnabar. Please note that I did not collect this entire boulder, but did collect some small samples for later examination under a polarizing compound microscope.

Mindat.org Photo of the Day - 30th Jun 2017
Photo ID: 825760     Uploaded by: Michael Cox   View Count: 901   Approval status: Public galleries    Type: Photo - 2560 x 1920 pixels (4.9 Mpix)

A2K-YLWSchuetteite, Quartz, Cinnabar, Corderoite, Quartz (Var: Chalcedony), Clays

McDermitt Mine, Opalite Mining District, Humboldt Co., Nevada, USA

Dimensions: 2.5 feet x 3 feet x 1.5 feet
Field of View: 3 feet
Largest Crystal Size: 3 mm
Weight: 500 lb

Photo taken by Mike Cox during geological examinations of the McDermitt open pit mine. Supergene schuetteite "blooms" on the southeast face of a boulder of Miocene silicified tuffaceous sediments containing cinnabar, corderoite, gypsum, and pyrite. Schuetteite blooms are surficial and somewhat seasonal. They seem to occur where the cinnabar and corderoite is soft and dusty (not highly silicified.) Cox has noticed that schuetteite blooms are thickest and most pronounced where gypsum and/or alunite occurs with concentrated but dusty colloidal cinnabar.
Photo ID: 825759     Uploaded by: Michael Cox   View Count: 74   Approval status: Public galleries    Type: Photo - 2560 x 1920 pixels (4.9 Mpix)

HVV-KPHQuartz, Cinnabar

McDermitt Mine, Opalite Mining District, Humboldt Co., Nevada, USA

Dimensions: 2.5 cm x 2 cm x 1.5 cm
Field of View: 1.2 mm
Largest Crystal Size: 7 mm
Weight: 13 g

Beautiful red cinnabar crystals included in quartz, as well as on the surface of the individual quartz crystals. The quartz has growth lines that suggest multiple episodes of alternating quartz growth and cinnabar deposition. There is an unknown white to transparent acicular radiating mineral at the top center of the photo. The quartz crystals occur in silicified vuggy lacustrine and fluvial deposits of volcanic ash from the Miocene eruption and collapse of the McDermitt caldera center.
Photo ID: 825733     Uploaded by: Michael Cox   View Count: 251   Approval status: Public galleries    Type: Photo - 2853 x 1903 pixels (5.4 Mpix)
Page 1 of 2 (1 to 10 of 15 total)
1 2

 
Mineral and/or Locality  
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Public Relations by Blytheweigh.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2019, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: July 23, 2019 14:26:04
Go to top of page