Archives

Posted by: Raymond McDougall on 10.23.2018 | Filed under: Latest, Recent Mineral Updates | Comments (0)

This Egypt Update (click here) features excellent goethite pseudomorphs after marcasite from the White Desert, north of Farafra Oasis.

This locality has been known for a number of years and pseudomorph specimens have come out once in a while. The pseudomorphs occur within the Cretaceous Khoman Chalk, from which the White Desert derives its name. Most crystals have typically been fairly indistinct, and to date sharp specimens have been relatively uncommon. These specimens, collected in 2013 and 2014, are remarkable for their relatively sharp marcasite crystal forms in aesthetic crystal clusters.

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt

 Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 7.0 cm

Over the years, these pseudomorphs have been variously labeled hematite, goethite and limonite (the latter no longer a valid mineral species name, but is a term still used in reference to unidentified iron hydroxides, so its use has not been incorrect). Recent work by Hannah Allen at Hamilton College has confirmed that the White Desert pseudomorphs are predominantly goethite. The small white grains lodged in among the crystal blades are barite, calcite and gypsum. (Allen, Hannah M., Pseudomorphed Mineral Aggregates of the Khoman Chalk, Western Desert, Egypt, Geological Society of America Abstracts with Programs. Vol. 46, No. 2, p.66 (2014)).

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt

 Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 5.4 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 6.1 cm

Although pseudomorphs after cubic and cuboctahedral pyrite crystals have also been found in the Khoman Chalk, the pseudomorphs after marcasite are more dramatic. These pseudomorphs are excellent specimens featuring beautiful marcasite crystal morphology, showing habits and forms exhibited by the crystallized marcasite specimens from the famous occurrences at Cap-Blanc-Nez, Pas-de-Calais, France.

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt

 Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 3.8 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 5.7 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, EgyptGoethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 6.5 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 4.5 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 4.1 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 3.6 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 3.8 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 3.1 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 3.0 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 3.0 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt – 3.3 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, Egypt
Same specimen as in the previous photo, bird’s eye view, 2.2 cm across

Posted by: Raymond McDougall on 10.17.2015 | Filed under: Latest, Recent Mineral Updates | Comments (0)

I’ve added a new USA Update (click here) with excellent specimens from various localities, most of which were collected between 25 and 50 years ago. Some of the specimens are from the collection of Robert Bartsch.

Rhodochrosite, American Tunnel  Mine , Silverton, Colorado, USARhodochrosite, American Tunnel Mine, Silverton, San Juan Co., Colorado – 12.5 cm
From the collection of Robert Bartsch

Microcline var. Amazonite with Smoky Quartz, Jack Rabbit Mine, Crystal Creek nr Crystal Peak, Lake George District, Teller Co., Colorado, USA.

Microcline var. Amazonite with Smoky Quartz, Jack Rabbit Mine, Crystal Creek near Crystal Peak,
Lake George District, Teller Co., Colorado – 5.7 cm
From the collection of Robert Bartsch

Microcline var. Amazonite with Smoky Quartz, Jack Rabbit Mine, Crystal Creek nr Crystal Peak, Lake George District, Teller Co., Colorado, USA.

Microcline var. Amazonite with Smoky Quartz, Jack Rabbit Mine, Crystal Creek near Crystal Peak,
Lake George District, Teller Co., Colorado – 4.8 cm
From the collection of Robert Bartsch

Mona Mine, Specimen Rock Area, nr Colorado Springs, El Paso Co., Colorado, USA

Microcline var. Amazonite, Mona Mine, Specimen Rock Area, near Colorado Springs,
El Paso Co., Colorado – 4.1 cm

Fluorapatite, King Lithia Mine, Greyhound Gulch, Keystone District, Pennington Co., South Dakota

Fluorapatite, King Lithia Mine, Greyhound Gulch, Keystone District, Pennington Co., South Dakota
Field of view approx. 3.5 cm
From the collection of Robert Bartsch

Fluorapatite, King Lithia Mine, Greyhound Gulch, Keystone District, Pennington Co., South DakotaFluorapatite, King Lithia Mine, Greyhound Gulch, Keystone District, Pennington Co., South Dakota
Crystal 1.1 cm
From the collection of Robert Bartsch

Millerite, Platte River, MissouriMillerite, Platte River, Missouri – crystal group 1.5 cm

Chrysocolla, Quartz, Planet Mine, Planet, Buckskin Mtns., La Paz Co., Arizona, USAChrysocolla, Quartz, Planet Mine, Planet, Buckskin Mtns., La Paz Co., Arizona
Field of view approx. 6 cm

Chrysocolla and malachite, Morenci Mine, Greenlee Co., ArizonaChrysocolla and malachite, Morenci Mine, Greenlee Co., Arizona – 4.9 cm

Fluorite, Cave-in-Rock District, Hardin Co., Illinois

Fluorite, Cave-in-Rock District, Hardin Co., Illinois
Field of view approx. 5 cm

Goethite, Goethite Hill, Lake George District, Park Co., Colorado, USAGoethite, Goethite Hill, Lake George District, Park Co., Colorado – 6.1 cm

Barite, Pack Rat Mine, Pryor Mtns, Carbon Co., Montana, USA

Barite, Pack Rat Mine, Pryor Mtns, Carbon Co., Montana
Field of view approx. 4.5 cm

Quartz, variety Herkimer Diamond, Crystal Grove, Lassellsville, Town of Ephrata, Fulton Co., New York, USA

Quartz, var. Herkimer Diamond, Crystal Grove, Lassellsville, Town of Ephrata, Fulton Co., New York
Crystal 1.2 cm

Posted by: Raymond McDougall on 09.23.2015 | Filed under: Latest, Recent Mineral Updates | Comments (0)

 

This Egypt Update (click here) features excellent new goethite pseudomorphs after marcasite crystals from the White Desert, north of Farafra Oasis, Egypt.

This locality has been known for a number of years and pseudomorph specimens have come out once in a while. The pseudomorphs occur within the Cretaceous Khoman Chalk, from which the White Desert derives its name. Most crystals have typically been fairly indistinct, and to date sharp specimens have been uncommon. These new specimens are remarkable for their relatively sharp marcasite crystal forms in aesthetic crystal clusters.

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate,  EgyptGoethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate, Egypt
5.7 cm

Over the years, these pseudomorphs have been variously labeled hematite, goethite and limonite (the latter no longer a valid mineral species name, but is a term still used in reference to unidentified iron hydroxides, so its use has not been incorrect). Recent work by Hannah Allen at Hamilton College has confirmed that the White Desert pseudomorphs are predominantly goethite. The small white grains lodged in among the crystal blades are barite, calcite and gypsum. (Allen, Hannah M., Pseudomorphed Mineral Aggregates of the Khoman Chalk, Western Desert, Egypt, Geological Society of America Abstracts with Programs. Vol. 46, No. 2, p.66 (2014)).

 Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate,  EgyptGoethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate, Egypt
4.7 cm

Although pseudomorphs after cubic and cuboctahedral pyrite crystals have also been found in the Khoman Chalk, the pseudomorphs after marcasite are more dramatic. These pseudomorphs are excellent specimens featuring beautiful marcasite crystal morphology, showing habits and forms exhibited by the crystallized marcasite specimens from the famous occurrences at Cap-Blanc-Nez, Pas-de-Calais, France.

 Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate,  EgyptGoethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate, Egypt
3.3 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate,  Egypt Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate, Egypt
6.5 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate,  EgyptGoethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate, Egypt
4.4 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate,  EgyptGoethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate, Egypt
4.2 cm

 Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate,  EgyptGoethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate, Egypt
4.9 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate,  EgyptGoethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate, Egypt
4.4 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate,  Egypt

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate, Egypt
3.6 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate,  EgyptGoethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate, Egypt
3.6 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate,  EgyptGoethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate, Egypt
3.0 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate,  EgyptGoethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate, Egypt
5.4 cm

Goethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate,  EgyptGoethite pseudomorph after marcasite, White Desert, north of Farafra Oasis, New Valley Governorate, Egypt
5.0 cm

Posted by: Raymond McDougall on 01.13.2015 | Filed under: Latest, Recent Mineral Updates | Comments (0)

I’ve added a new Morocco Update (click here) with some particularly fine specimens. I have managed to obtain five more blue barites from the Sidi Lahcen Mine in Nador that are worthy of including on the site. Although almost all barites from Sidi Lahcen have some amount of damage (many are badly damaged) these ones are in excellent condition – they are great high-quality pieces.

Barite, Sidi Lahcen Mine, Nador, Morocco

Barite, Sidi Lahcen Mine, Nador, Morocco – 10.7 cm

Barite, Sidi Lahcen Mine, Nador, Morocco

Barite, Sidi Lahcen Mine, Nador, Morocco – field of view approximately 10 cm

This update includes several wonderful individual specimens. A startling hot pink cabinet specimen of cobaltoan dolomite from Bou Azzer, a super sharp thumbnail-sized specimen of, and also a great glassy miniature of green fluorapatite from Imilchil, a sharp, gemmy brown titanite from Imilchil, a Tounfit fluorite that will have you looking a while to sort out the morphology, and an unusually fine specimen of sprays of goethite crystals included in quartz crystals from Tizi-n-Tichka.

Dolomite, var. Cobaltoan Dolomite, Agoudal Mine, Bou Azzer District, Ouarzazate Province, Morocco

Dolomite, var. Cobaltoan Dolomite, Agoudal Mine, Bou Azzer District, Ouarzazate Province, Morocco – 10.8 cm

Fluorapatite, Anezmy, Imilchil, Morocco

Fluorapatite, Anezmy, Imilchil, Morocco – 4.3 cm

Fluorapatite, Anezmy, Imilchil, Morocco

Fluorapatite, Anezmy, Imilchil, Morocco – 3.0 cm

Titanite, Imilchil, Er Rachidia, Morocco

Titanite, Imilchil, Er Rachidia, Morocco – largest crystal 1.5 cm

Goethite, Quartz, Tizi-n-Tichka, Ouarzazate, Morocco

Goethite in Quartz crystals, Tizi-n-Tichka, Ouarzazate, Morocco

Fluorite, Tounfit, Boumia, Khenifra, Morocco

Fluorite, Tounfit, Boumia, Khenifra, Morocco – crystal approximately 1 cm

Finally in this update, I have included a group of new specimens of yellow fluorite cubes with barite and quartz. Although Moroccan yellow fluorite is often attributed to “Aouli”, an abandoned historical mining complex which is not producing specimens, contemporary specimens are in fact from an area near Sidi Ayed. It is road-accessible, but it is relatively remote in a barren, windswept area, which sees sandstorms in the dry weather and roads washed out in the rain. These fluorites are nice for Sidi Ayed specimens, for a few reasons – they are isolated on quartz crystals rather than massed together, some of the quartz has some nice red colouring from hematite, and a few of the crystals show tiny irregular zones of greenish blue colour.

Fluorite, Sidi Ayed, Boulemane, Morocco

 

Fluorite, Sidi Ayed, Boulemane, Morocco – crystal 0.8 cm

Fluorite, Sidi Ayed, Boulemane, Morocco

Fluorite, Sidi Ayed, Boulemane, Morocco – crystal 1 cm