Mineral suite
Carlsbad twinned Feldspars
Subcollection/suite focusing on the Carlsbad twinning habit of the feldspar group. This shape and form of twinning attracted me for years and I find it to be really interesting. Specimens on this page are not for sale.
CT01
Orthoclase
West Maroon Pass Area, Pitkin County, Colorado, USA
Specimen from the Rock Currier stock, with a great form and no significant damage. A great example of the Carlsbad twinning habit with a manganese dendrite or two on the back of the specimen.
CT02
Orthoclase
Erongo Mountains, Karibib Constituency, Namibia
Carlsbad twin of orthoclase with a very interesting texture accompanied by a flawless aquamarine on top of it, making a special appearance and contrast.
CT03
Epidote
Rusted Revolver Prospect, Orogrande, New Mexico, USA
An amazing example of this material. Flawless pseumorph of epidote after othoclase. Shows great twinning, no damage on the crystals and a great representation of the material.
CT04
Sanidine
Elbrus caldera, Elbrus Mt, Kabardino-Balkaria, Russia
A well-formed pair of twinned sanidine crystals forwarded to me by my friend and mineral photographer Matthew P. at the Munich mineral show in 2023.
CT05
Topaz
Saubachriss, Muldenberg, Vogtland, Saxony, Germany
An absolute classic and something you can’t miss if you like German classics, Carlsbad twins. Pseudomorph of topaz after orthoclase, twinned and complete.
CT06
Orthoclase
Col. Notre Dame, Cevernes, France
Sharp and glassy twin with a great combination of dark surface with white spots over it, creating a good contrast.
CT07
Sanidine
Samothrace, Evros, Eastern Macedonia and Thrace, Greece
Outstanding example of sanidine, collected and gifted to me by my favorite professor (Kristina R. Š.) from the University of Geology in Belgrade.
CT08
Orthoclase
West Maroon Pass Area, Pitkin County, Colorado, USA
Flawless, sharp and really well balanced twin from an old collection. The first Carlsbad twin in my collection that started it all.
CT09
Orthoclase
Col. Notre Dame, Cevernes, France
Orthoclase with a really interesting red color that is specific for this locality in France.
CT10
Orthoclase
Leadville, Lake County, Colorado, USA
An orthoclase twin from a pretty common locality with a pretty common look. The only thing making it special are the few manganese dendrites covering it’s surface.
CT11
Sanidine
Highwood Mountains, Chouteau County, Montana, USA
Really sharp and nice twin of orthoclase from a not-so-common locality. What makes it even more special is that it was gifted to me by my friend Efren Flores.
CT12
Orthoclase
Organ View Prospect, Otero County, New Mexico, USA
A small twin of orthoclase perched on top of some green-ish matrix. It is always pleasant seeing these twins on top of some matrix.
CT13
Orthoclase
Afloramiento de la Machiota Baja, Zarzalejo, Madrid, Spain
An orthoclase from Spain gifted to me on one of my trips to Barcelona. The gift was given to me by a seller (Isidro) in a mineral shop in Barcelona. It was really nice going through all the flats in the shop.
CT14
Quartz
Malpartida de Corneja, Ávila, Castile and Leon, Spain
Interesting specimen with a pale-red color. Here we can see a pseudomorph of quartz after orthoclase, still showing the great twinning. Specimen was collected by Erin and Phil from Enchanted Minerals.
CT15
Orthoclase
USA
A bit different look on this twin, both regarding color and shape. It was a pleasant surprise finding this one for sale without even looking for it.
CT16
Orthoclase
Mount Malosa, Zomba, Southern Region, Malawi
Snow-white orthoclase crystals with porcelain lustre showing a great and sharp Carlsbad twin with a black and lustrous crystal of aegirine, creating a nice contrast.
CT17
Orthoclase
Crystal Pass area, Goodsprings, Clark County, Nevada, USA
Interesting twin of orthoclase from Nevada. This specimen was feautured in the Young Mineral Collectors case at the Tucson mineral show in 2022.
CT18
Orthoclase
Highwood Mountains, Chouteau County, Montana, USA
Really sharp and nice twin of orthoclase from a not-so-common locality. What makes it even more special is that it was gifted to me by my friend Efren Flores.
CT19
Microcline
Tongbei, Yunxiao, Fujian Province, China
Two twinned microcline crystals with a subtle color on top of some matrix and a small quarty crystal.
CT20
Topaz
Muldenschlag, Klingenthal, Saxony, Germany
Interesting partial pseudomorph of topaz after orthoclase showing a contact Carlsbad twin. It came together with an interesting old label.
CT21
Orthoclase
Afloramiento de la Machiota Baja, Zarzalejo, Madrid, Spain
An orthoclase from Spain on top of some matrix creating a great specimen. This specimen was purchased in Madrid, Spain by me at a small local mineral show that is taking place every first weekend of the month.
CT22
Orthoclase
Kirnbargsee, Braunlingen, Germany
Simple, yet great specimen of orthoclase from Germany. Specimens that are this simple and have such a complete and elegant form remind me why I’m so into this type of twinning habit.
CT23
Kaolinite
England
A real classic. Pseudomorph of kaolinite after orthoclase showing a great twinning habit. These specimens are often called “pig’s egg”.
CT24
Sanidine
Puy de Sancy, Chastreix, Issoire, Puy-de-Dôme, France
Sharp and clean cyclic twin of sanidine from a classic French locality. The way this specimen is formed makes it look like a piece of art.
CT25
Orthoclase
Red River District, Taos County, New Mexico, USA
Twin of orthoclase with a slight hint of green color covered in mangenese dendrites, creating a fun composition. Specimen was collected by Erin and Phil from Enchanted Minerals.
CT26
Orthoclase
Cinco, Fremont Valley, Kern County, California, USA
Specimen that is in a really good shape, collected by Earl Pampeyan, 1946. Ex. California Academy of Sciences, Ex. Steve Pullman.
CT27
Orthoclase
Erongo Mountains, Karibib Constituency, Namibia
Carlsbad twin of snow-white orthoclase accompanied by a flawless aquamarine on the side of it, making a special appearance and contrast.
CT28
Sanidine
Kakourou Peak, Promachoi, Pella, Central Macedonia, Greece
Flawless, really sharp crystals of orthoclase on top of some trachite matrix creating an amazing arrangement and piece of nature’s art.
CT29
Orthoclase
Loket, Sokolov District, Karlovy Vary Region, Czech Republic
Twinned orthoclase from a classic and most famous locality for this type of twinning in feldspar. Specimens from this locality are quite easy to find, but it’s still a challenge to find a flawless piece.
CT30
Sanidine
Shingle Creek, British Columbia, Canada
Specimen that was sent to me by a good friend (Allan Smith) from Canada as part of a trade. It was collected in 1988. and ended up in my collection.
CT31
Orthoclase
Ottenstein Reservoir, Zwettl, Lower Austria, Austria
Something you don’t see so often from Austria, especially not in this quality. The similarity to the Czech twins was interesting to me, having in mind how the locality is close to the Czech republic.
CT32
Kaolinite
Melbur Quarry, Cornwall, England
A real classic. Pseudomorph of kaolinite after orthoclase showing a great twinning habit. These specimens are often called “pig’s egg”. This specimen was a gift from my friend Forrest Carithers, and was part of the Cook collection.
More photos left to add to the subcollection/suite
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Learn more about
Feldspar Group
Group of aluminium silicate mineral that include mineral species like sanidine, microcline, orthoclase, etc.
Information
Feldspar is the name of a group of aluminium silicate minerals and is collectively the most common mineral group found on the surface of the Earth. The major rock-forming minerals in the Feldspar group include albite, anorthite, orthoclase and microcline.
In petrology the group is split into two major subgroups: Alkali feldspar – feldspar minerals poor in calcium, and mostly rich in potassium.
At high temperature the alkali feldspars form a series from sanidine to high albite; the series is incomplete at low temperature. Some workers include barium feldspars (celsian and hyalophane) and probably the rubidium feldspar rubicline, as alkali feldspars.
Plagioclase – the albite to anorthite series.
Feldspars may contain very minor amounts of OH groups, considered as defects (e.g., Yang et al., 2015).
Origin of name: The name Feldspar is derived from the German term ‘feldspat’.
Text and illustration owned by mindat.org
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