Psuedomorphs & Mineral Oddities

click on image for larger view

C-273  Calcite with sand inclusions  $60  $40

Rattlesnake Butte, Jackson County, SD

6.2 x 5.5 x 2.7 cm

A sculptural pair of interconnected, scalenohedral Calcite crystals. The Calcite grew in a sand matrix, capturing the sand as it formed making for an unusual specimen. Sand Calcites are poikiloblastic Calcite crystals included by a large amount of Quartz sand, sometimes exceeding 50%. These specimens were collected heavily in the 1960s-1970s but are seldom seen these days as much of this area is within an Indian reservation and collecting is prohibited.

 

click on image for larger view

F-295  Orthoclase replacing Marialite  $50  $25

Pitwak Mine, Ladjuar Medam, Sar-e Sang, Koksha Valley, Badakhshan, Afghanistan

4 x 4 x 3 cm

A group of Marialite crystals from small finds made 7-8 years ago. The Marialite crystals are pseudomorphing to Orthoclase. This specimen seems to have almost completely altered to Orthoclase as very little fluorescence is observed. The blue color of these specimens is thought to be most likely due to minute Fe impurities that transition between Fe+2 and Fe+3.

click on image for larger view

AD-226  Quartz pseudomorph after Apophyllite  $135  $95

Summer Storm Claim, Challis, Bay Horse Mining District, Custer County, ID

12.8 x 13.7 x 9 cm

A large and fully intact vug of Apophyllite crystals that have been completely replaced by Quartz. Also present in this specimen are several flattened Calcite crystals set deep inside the vug. These pseudomorphs were a limited find made by John Cornish (Rat's Nest Claim Heulandite) in the early 2000's. This was, according to the miner, the only intact vug recovered from this find.

click on image for larger view

C-316  Elbaite & Quartz on Cookeite cast after Tourmaline  $150  $100

Araçuaí, Minas Gerais, Brazil

12.9 x 7.6 x 5.2 cm

A vug of Cookeite that once encased a large Tourmaline crystal that dissolved away leaving a bed of greenish-blue Elbaite on the lower front portion of the specimen. The termination of this specimen features a 2 cm Tourmaline crystal that has been replaced by Lepidolite. Also present on the Cookeite “shell” are several groups of Quartz crystals.

click on image for larger view

M-076  Muscovite var. Sericite pseudomorph after Tourmaline  $300  $175
Ex. R. Whitmore Collection
Ex. Russ Rizzo Collection

Noyes Mountain Quarry, Greenwood, Oxford County, ME

7 x 6.8 x 6.2 cm

A good-sized Tourmaline crystal that has been partially replaced by silvery-green crystals of Sericite (a variety of Muscovite). This specimen has a shallow termination on the upper portion with a more crudely-formed termination on its bottom. The composition of the Tourmaline from this location is an intermediate between Schorl and Dravite. These specimens were collected in the early 1980's and are highly prized by collectors. This quarry was worked briefly by Loren Merrill and Arthur Valley in 1921-1922 for the benefit of Kenneth K. Landes, then a Harvard University student. Landes' dissertation, Paragenesis of the Granitic Pegmatites of Central Maine (American Mineralogist, 1925, v. 10, p. 355-411) was based on this quarry and the Bennett Quarry in Buckfield and his thesis revolutionized ideas about how pegmatites crystallize.

click on image for larger view

C-310  Calcite pseudomorph after Ikaite (Glendonite)  $40  $25

Carter Creek, North Slope Borough, AK

7.3 x 2.4 x 2.4 cm

A doubly-terminated pseudomorph/alteration specimen of "Glendonite" from one of America's northernmost mineral localities. These specimens start out as the mineral Ikaite which is calcium carbonate but with a handful of water molecules attached to it. Once the Ikaite reaches a temperature above 8°C (46°F), it alters to Calcite.

click on image for larger view

T-308  Schorl with Beryl inclusion  $60  $40

Dara-i-Pech Pegmatite Field, Chapa Dara District, Konar Province, Afghanistan

2.8 x 2.4 x 2.5 cm.

Just when you think that you've seen it all from Afghanistan, there's this specimen   A lustrous crystal of Schorl that is include by a clear, colorless Beryl crystal.  The Beryl continues down the length of the specimen with a small portion protruding from the Schorl's bottom.  Another neat feature of this specimen are the pronounced and well-formed growth hillocks on its beveled termination.  I have sold a good amount of material from Afghanistan over the last 27 years and I have only seen one other specimen like this.

click on image for larger view

Q-451  Chalcedony pseudomorph after Anhydrite  $120  $80

Agua Fria River, New River Station Area, Yavapai County, AZ

4.5 x 4.3 x 2.6 cm

These dramatic Chalcedony pseudomorphs after Anhydrite were collected over a period of 10 years by my friend, Al Rose. This material has the distinction of being mentioned not once but twice in The Mineralogical Record's what's new in minerals. Not many of these were found and are much sought after by collectors of Arizona minerals as well as by pseudomorph collectors.

Q-552  Quartz pseudomorph after Gypsum (fluorescent)  $50  $25

Crawford Dam, Crawford, Dawes County, NE

9.5 x 8.7 x 7 cm

Nebraska is not necessarily the first state that one thinks of when it comes to mineral specimens, but these pseudomorphs from Crawford are some of the more noteworthy specimens from anywhere in the Cornhusker State. This piece is a group of what were originally Gypsum blades that were completely replaced by Quartz. Areas of the interior portion of this specimen exhibit yellowish fluorescence under LWUV light and other areas have bright green fluorescence under SWUV illumination which suggests that specimen is made up of both Chalcedony and Quartz. Fluorescence in Quartz is rarely observed.

click on image for larger view

F-286  Orthoclase pseudomorph after Leucite (Pseudoleucite)  SOLD

Kalehöyük, Kaman District, Kirsehir Province, Turkey

6.2 x 6.1 x 5.5 cm

A single equant crystal of Leucite that has been replaced by chalky white Orthoclase. A very rare and fine pseudomorph from an obscure locale.

click on image for larger view

Q-443  Amethyst cast after Calcite  SOLD

Artigas, Artigas Department, Uruguay

7.5 x 4.1 x 3.5 cm.

Here we have a complete all-around Amethyst cast after Calcite.  This specimen consists of a tower of numerous medium-purple Amethyst crystals.  If you look up the bottom of the specimen you will see the sharp, pseudohexagonal form of the dissolved Calcite crystal.  The Calcite was completely etched away by corrosive solutions in the pocket, leaving the Amethyst.  These specimens are one of nature's better looking mineral oddities.

click on image for larger view

Q-558  Quartz (modified by lightning)  SOLD

Serra de Espinhaco Mountains, Diamantina, Minas Gerais, Brazil

12 x 4 x 3.1 cm

An example of Quartz that, inside the rock where it was formed, was submitted to a high electrical voltage created by lightning hitting the rock (not the Quartz crystal). Due to its piezoelectrical properties, the Quartz crystal submitted to this high voltage will expand or contract (depending on the signal of the electrical field, positive or negative). The result is a weird crack pattern that develops on the crystals faces of the Quartz. For many years, crystal miners in the Serra de Espinhaco Mountains of Brazil, where there are frequent thunderstorms, have reported finding these oddities. But only in the last 8-10 years have any, in limited quantities been available to collectors.

The Espinhaco Mountains are constantly affected by orographic thunderstorms, which generate a high number of lightning bolts. These orographic flashes have some special properties: they reach speeds of up to 160,000 m\s and thereby generate plasma temperatures of 30,000 ° C in nanoseconds. There is a paper about these type of crystals that was published by Prof. Joachim Karfunkel et. al., from University of Minas Gerais, who found the explanation for these weird crack patterns. You can read about it (in German) here: Link to article

Return to Mineral Specimen Galleries