Category Archives: Mineral localities

Rare fluorite

How to differentiate the fluorite specimens from Asturias. First post, COLOR!

As Wendell Wilson wrote recently in his High End Report Tucson Show 2014  “Color is King […]” and I think most mineral collectors will agree with his statement. Even more if we are speaking about fluorite specimens!

This is the first post about how to differentiate the fluorite specimens from Asturias, Spain. Today, I will focus in the wide  colour range of fluorite crystals. In others posts I will speak about crystallization, mineral association, etc.

As you all probably know, fluorites crystals from Asturias, an small region in the north of Spain, rank between the finest cubic fluorites in the world.

Situation of Asturias in Spain
Asturias region (surrounded by red lines), north of Spain. Google Maps.

There are some other fluorite localities in Spain, outside Asturias region, but they are not very well known for gemmy crystals and the quality is usually low. So we will focus only on the colour of the fluorites from the fluorspar deposits of Asturias, Spain.

Fluorite collectors from overseas usually get confused about the fluorite localities in Asturias. So many localities, so many mislabelled specimens. So this is a problem for a collector concerned with the origin of his fine fluorite specimens.

There are many obscure fluorite localities in Asturias but we will keep it simple for this post. To start with, I am going to let you know the four most famous localities nowadays. Each one produces quite different specimens, but sometimes is very difficult to assure the exact locality of a specimen.

1- La Collada . La Collada mining area comprises several fluorspar mines. Usually fluorites from La Collada range between blue and  violet, but dull green hues are not specially rare. Zoned crystals are common. It is not very difficult to find blue and violet or light blue and dark blue in the same crystal.

fluorite dodecahedron faces la collada
Level 75, Josefa Veneros vein, La Collada. Note the purple-violet coloured dodecahedron faces. Fernandez Buelga Mineral Collection specimen. Carlos Casariego photo.

General note for the green fluorites from La Collada: Dull green crystals are not rare, specially in some old areas; but vivid, bright greens, are exceptionally rare. Nowadays, green coloured crystals are rarely seen in the mineral specimen market.

Green fluorite from Corta la Sirena, La Collada
Green fluorite from “Corta la Sirena”, La Collada de Atras, La Collada. Fernandez Buelga Mineral Collection specimen. Juan Fernandez Buelga photo.

Note: La Viesca Mine has been worked as an open pit and underground mine. It is inside of La Collada mining area. It usually produces from very light to very dark blue – violet coloured crystals. Purple colour is uncommon. Blues with a hint of green are scarce. Small colourless crystals are common, but large ones are quite uncommon. Highly saturated light blue crystals are rare.

The colour violet. Source Wikipedia.
The colour violet. Source Wikipedia. See
Saturation scale
Saturation scale. Source: – See:
Incolore fluorite
Incolore or very pale blue coloured fluorites are common in La Viesca. Juan Fernandez Buelga photo and specimen.
Fluorite with highly saturated blue phantoms
Fine saturated light blue phantoms inside a light blue crystal. Uncommon. Note the outer dark blue phantom. Juan Fernandez Buelga photo and specimen.
Blue fluorite
Intense blue coloured fluorite crystal from La Viesca. Juan Fernandez Buelga photo and specimen.
Fluorite colored by odd inclusions
There are numerous color zones within the crystals of this rare fluorite: starting with light violet, dark violet, and then light blue. Red and yellow areas due to inclusions. La Viesca, La Collada. Juan Fernandez Buelga photo and specimen.
Fine fluorite on quartz, Asturias
Highly saturated medium blue with a hint of green. Note the blue phantom. La Viesca. Juan Fernandez Buelga photo and specimen.
Top quality fluorite
Saturated light to medium blue with a hint of green. Note the blue phamton with different intensity zones. Juan Fernandez Buelga photo and specimen.


2- Berbes mining area. Blue, violet and purple fluorite crystals, being the last probably the rarest, although pure blue is not common either. As a general and easy rule I could say that the closer to the red spectrum the rarer it is.  Berbes area tends to the red spectrum (purple) much more than La Collada.

Purple colour. Source Wikipedia.
Purple colour. Source Wikipedia. See

Zoned fluorite crystals in Berbes are common, but to find two different colours in the same crystal is unusual. Let me explain: You can find light purple crystals with a medium or dark purple phantom. The same stands for violet or blue. But to find a blue crystal with a purple or violet phantom is uncommon.

Intense violet colour. Berbes.
Intense violet colour. Berbes. Juan Fernandez Buelga photo and specimen.
Purple fluorite
Highly saturated violet colour. Rare. Juan Fernandez Buelga photo and specimen.
Purple fluorite
Purple fluorite from Berbes. Fernandez Buelga Mineral Collection. Carlos Casariego photo.
Pink fluorite
Purple fluorite, close to pink colour. Note the finer phantoms of the same colour. Fernandez Buelga Mineral Collection. Carlos Casariego photo.

3- La Moscona Mine. Almost all fluorites from this underground mine are yellow. Ranging from pale and greyish yellow to honey coloured or extremely vivid yellow, being probably this last one the rarest among the yellows. Rarely, you can also find dark blue (with more or less violet – purple component)) and strong red.

Red fluorite
Average yellow and rare red areas. La Moscona Mine. Juan Fernandez Buelga photo and specimen.
Rare fluorite
Rare combination of highly saturated dark violet and yellow. La Moscona Mine. Juan Fernandez Buelga photo and specimen.

Usually zoned fluorite crystals in La Moscona Mine show different shades of yellow – honey colour. Much more rare are specimens showing reddish phantoms, being the rarest the blue – yellow phantoms.

Honey yellow fluorite
Yellow and honey coloured fluorite cluster from La Moscona Mine. Juan Fernandez Buelga photo and specimen.

Note: Villabona Mine is a different fluorspar mine  near Moscona Mine. Based on the specimens I would say that both mines operate the same fluorspar deposit. There are only around five kilometres between the entrance of the two mines. Specimens from these two localities are very difficult to distinguish. We could say that fluorite crystals from La Moscona Mine usually tend to warmer yellows (honey, reddish), whereas Villabona tend to cooler yellows (very light hints of green).

As I mentioned before, to differentiate fluorite specimens from La Moscona and Villabona is a very difficult task, even for experts! As a very personal note, I would say that is imposible to differenciate specimens from one and other locality as a whole! You can spot specimens from one and the other, based on famous pockets for example, but everyone will fail sooner or later.

Rare calcite with fluorite
As you can see the colour of this fluorite from Villabona Mine is the same as many other specimens in Moscona Mine. However the calcites of this sample are rare. Juan Fernandez Buelga photo and specimen.

4- Emilio Mine. The most common colour in this underground mine is the lack of colour! Usually greyish and sometimes gorgeous water clear fluorite crystals. Light blue is not uncommon, being dark blue quite uncommon, but not rare in some areas of the mine. As a general rule for this mine: colours are light.

Fluorite with inclusions
Gorgeous Emilio Mine specimen showing the characteristic grey colour and a outer water clear phantom, very difficult to appreciate in the photo. Note the bitumen inclusions all over the specimen, between the grey and water clear crystallization phases. Juan Fernandez Buelga photo and specimen.

Note: Jaimina Mine is a fluorspar underground mine very near Emilio Mine. Indeed one connects or almost connects  with the other, although mine entrances are two kilometres away from each other. To distinguish between fluorite specimens from Jaimina and Emilio is practically impossible. The same “La Moscona – Villabona issue” here. Of course, you can distinguish pockets but not the specimens from either locality as a whole. As a very general and unprecise opinion, fluorite pockets in Jaimina tend to warmer blues, whereas Emilio tend to cooler blues. Could this be due to Jaimina being closer to Berbes than Emilio?

I hope you enjoyed this post. If you have any comments, ideas or suggestions please feel free to send me an email.

New photos will be added to this post in a near future. Stay tuned and sign up with us in our home page.

Juan Fernandez Buelga

Many of the fluorspar mines of Asturias are closed, being others active. Mineral collecting in them is forbidden by the mining companies which operate the mines and the Spanish law.


New find from the Panasqueira Mine, green to bluish quartz

An small new find with with dark green bluish quartz crystals was found in the famous Panasqueira Mines during late 2013.

Green quartz Panasqueira
Large green bluish quartz crystal with calcite  found at the Panasqueira Mine. Size: 9.5 x 8 x 7.5 cm. Fernandez Buelga Mineral Collection specimen. Juan Fernandez Buelga photo.

Panasqueira is well known for its superb colorless and trasparent quartz crystals (See article about the Panasqueira Mines in the Mineralogical Record Vol.45, 1 by Jordi Fabre and Carles Curto).

Well crystallized inclusions are not rare (see photo below) but coloured crystals are a novelty from this mine. At the moment it is not known which mineral causes this nice green bluish colour.

Arsenopyrite inclusions in a quartz from the Panasqueira Mine
Well formed arsenopyrite crystals included by colorless quartz. Panasqueira Mine, Portugal. Juan Fernandez Buelga photo.
Green quartz Panasqueira
Detail of a green bluish quartz crystal with other less included sidecar crystals. FOV 2 cm. Juan Fernandez Buelga photo.

The collected specimens are associated with two different generations of what it seems to be calcite. Some of them present colorless apatite crystals and very minor sulfides.

Green blue quartz crystal Panasaqueira
This one shows an special intense blue- green color plus minor calcite crystals. 4.3 x 4 x 2.5 cm. Spanish Minerals specimen. Juan Fernandez Buelga photo.


Juan Fernandez Buelga






Panasqueira Mine, Portugal – Say hello to the beautiful world of Panasqueira minerals!


Mining began in the district in 1898 but probably the Panasqueira mines (Portugal) were first worked for tin by the Romans and next by the Moors. In 1927 the mining concessions were taken over by Beralt Tin and Wolfram, Ltd. (a british company). Today Panasqueira is one of the biggests tungsten mines in the world and it is being operated by Sojitz Coorporation, a japanese company. The Panasqueira district have indeed several mines, known as Corga Seca, Barroca Grande, Panasqueira, Vale da Ermida and smaller ones. Some of them have closed many years ago like for example Val da Ermida, this last mine produced some of the best mineralogical examples of all Panasqueira district history.

The old Panasqueira Mines village in the 50's, some miners still live here but the majority of them has moved to Barroca Grande village, where the main mine entrance is nowadays.
The old Panasqueira Mines village in the 50’s, some miners still live here but the majority of them has moved to Barroca Grande village, where the main mine entrance is nowadays.
Panasqueira Mine
The above mentioned village today. Long time ago hundreds of people lived there now just a few. Behind the tree you can see the old cinema. Juan Fernandez Buelga photo.

The ore deposits of the Panasqueira district are the leading source of tungsten in western Europe. The Panasqueira district is located in the Beira Baixa province about 34 km west of the city of Fundao, Portugal.

Old entrance of the famous Panasqueira Mine, Portugal
Old mine entrance

At least since 70´s the Panasqueira Mines are known among mineral collectors for the beauty of the minerals found there. In my personal opinion Panasqueira has given many of the best apatites in the world, but this mine is not only about apatites, it has produced a exceptionally large suite of other minerals that they also rank as the very best for the species. However the ammount of fine crystallized different minerals you can find in just one specimen is what sets apart this locality.

apatite panasqueira mine portugal
Blue greenish apatite on siderite crystals from the famous Panasqueira Mine. Spanish Minerals specimen. Juan Fernandez Buelga photo.

Sadly, the way mining companies have been operating this deposit does not help protecting the mineral art these mountains hide. Furthermore miners can loose their jobs if they remove minerals from the mine. Nevertheless miners risk their positions taking out a few specimens just to earn a few more euros to compesate their low salaries. These conditions plus the lack of time end up in a shortage of minerals where most of them are severely damaged. The situation is so bad that trading of minerals from the mine or visiting old mine workings is an offence, this makes Panasqueira mineral collecting even harder now..

Purple apatite, Panasqueira Mine
Violet apatite with quartz. Panasqueira Mine, Portugal. Spanish Minerals specimen. Photo, Juan Fernandez Buelga.
Superb arsenopyrite with minor quartz, siderite and fluorite. Panasqueira Mine. Spanish Minerals specimen, Juan Fernandez Buelga photo.
Superb arsenopyrite with minor quartz, siderite and fluorite. Panasqueira Mine. Spanish Minerals specimen, Juan Fernandez Buelga photo.

Geology of the mining district

The surface geology of the Panasqueira district is restricted to the tightly folded vertically-dipping pelitic Beira Schist which suffered greenschist-grade, regional metamorphism during the early compressive stages of the Hercynian orogeny. Original lithologies were principally argillaceous to arenaceous shales, graywackes, and fine grained sandstones. Taken as a whole this sequence, which is widespread in Portugal, has been referred to as the Beira Schist complex.

Although no granite crops out in the district, a granite cupola (Panasqueira granite) has been identified at shallow depths in the Panasqueira mine and is at least spatially related to the mineralization. Pervasive hydrothermal alteration of the Panasqueira granite prevents its lithologic correlation with other intrusive facies of the Hercynian granitic complex exposed elsewhere in Portugal. However, from its undeformed condition and the fact that it utilized late (post-regional metamorphic) joints in its emplacement, the granite was clearly intruded after the main compressive stage of the Hercynian orogeny. Isotope studies suggest that the Panasqueira granite is an S-type granite.

Map of Portugal showing location of Panasqueira and the distribution of Hercynian granitic rocks
Map of Portugal showing location of Panasqueira and the distribution of Hercynian granitic rocks

Structure of mineralization

The prevailing horizontality of the Panasqueira veins is a feature of this district which sets it apart from other tin-tungsten deposits. The veins, which range in width from a few milimeters to more than a meter, cut across the altered granite cupola and steeply dipping Beira Schist thereby indicating the mineralization ocurred after emplacement and crystallization of the pluton.

panasqueira estructure 2
panasqueira estructure 1 Cross section of the Panasqueira cupola silica cap and cross-cutting flat veins.

Because the mineralization is open-space filling rather than replacement, this presents a special problem as to how the structures were initially dilated and then managed to remain open during the subsequent mineralization. Evidence suggests that the flat vein openings were created and supported by hydraulic pressures of the early tin-tungsten vein fluids (fluid pressures exceeded lithostatic pressures).

Mineralogy of the veins

Over fifty mineral species have been described from the Panasqueira deposits. Due to the coarse-grained nature of the minerals, the Panasqueira deposits have been known for their good mineral collecting. Although there is a rather complex paragenesis, the mineralogy is uniform laterally, composed dominantly of quartz. with lesser amounts of muscovite, topaz, tourmaline, carbonates, apatite, wolframite, cassiterite, and sulfides.

Green quartz from Panasqueira Mine
Sometimes small pockets with mineral rarities come up like this green – bluish quartz with brown calcite from the Panasqueira Mine. Spanish Minerals specimen, Juan Fernandez Buelga photo.

Vein paragenesis and alteration

The paragenesis is fairly complex because several minerals, including quartz, muscovite, and pyrite, were long-lived in the sequence and were precipitated in a repetitive manner. In spite of these complexities, four main stages of mineralization have been recognized and described: (1) the oxide-silicate stage, (2) the main sulfide stage, (3) pyrrhotite alteration stage, and (4) late carbonate stage. Economically, the first stage was by far the most important, because it includes the ore minerals cassiterite and wolframite.

Ferberita Panasqueira. Artículo
Superb ferberite with marcasite. Panasqueira Mine. Fernandez Buelga Mineral Collection specimen. Juan Fernandez Buelga photo
Green apatite, Panasqueira Mine, Portugal
Green apatite, Panasqueira Mine, Portugal

20140226_panasqueira_update1 (18)

20140226_panasqueira_update1 (17)
This specimen is one of the most aesthetically appealing apatites included by greenish schorl I have ever seen. The tourmaline acicular crystals have crystallized around the bases and inside of the glowing apatites. I like the stark contrast between the green inlcuded ones (near the thin rock matrix) against the big incolore one, which is far from the green schorl crystals so not included by them. Spanish Minerals specimen, Juan Fernandez Buelga photo.

Click here to see other high quality minerals from the Panasqueira Mine:



“La mina más antigua en el mundo”

“La mina más antigua en el mundo.” Así describe a la mina de Almadén Don Santiago de Alvarado y de la Peña en 1832.

El Reino Mineral o sea la mineralogia en general y en particular de España. Don Santiago de Alvarado y de la Peña

Y así sigue..

“ALMADEN. La famosa mina de cinabrio, mercurio o azogue de la villa de Almadén, en la provincia de La Mancha, partido de Ciudad-Real, en el arzobispado de Toledo, merece ocupar el primer lugar, como que, según dice el ilustre Bowles, es la más rica para el estado. La más instructiva en su labor, la más curiosa para la historia natural y la más antigua que se conoce en el mundo. Teofrasto, que vivía trescientos años antes que J.C., habla del cinabrio de España; y Vitrubio, contemporáneo de Augusto, hace también mención de él. Los romanos creían que el mercurio era veneno, pero no obstante sus matronas se afeitaban (pintaban) los rostros con el cinabrio, y los pintores lo usaban para sus colores.

photo 1

Cinabrio cristalizado de la mina de Almadén. Simonin’s Mines and Miners: Or Underground Life. 1869

Plinio dice positivamente que esta mina, de que hablamos, se cerraba y sellaba con la más exquisita custodia; y que solamente se abría para sacar la cantidad suficiente de cinabrio que se había de enviar a Roma. Es constante que labraron esta mina los romanos; pero después acá es tanto lo que en ella se ha revuelto que no quedan indicios de sus trabajos. Los moros no parece que la cultivaron, y quizá sería por la preocupación, que aun subsistía en su tiempo, de que el mercurio era veneno. La iglesia y gran parte de la villa (que es de 1987 vecinos u 8448 habitantes, según Miñano) están sobre el cinabrio, y todos ellos subsisten de la mina. Esta se comprende en un cerro de peñas de arenas que forman dos planos inclinados, y en la cima sale una cresta de peñas peladas en que se ven algunas pequeñas manchas de cinabrio, que naturalmente servían de indicios a los primeros descubridores de las minas: por lo restante del cerro se ven algunas vetillas de pizarras con venas de hierro, las cuales en la superficie siguen la dirección de la colina.


1768 Antique Copper Etching of Mercury Mine in Almadén, Spain, by Benard after Goussier from “Encyclopédie” of Diderot and d’Alembert

Todo este país abunda en minas de hierro; y lo que es más en la misma mina de Almadén se hallan a veces pedazos en que el hierro, el azogue y el azufre están tan mezclados entre sí que no forman cuerpos diferente. Los cerros vecinos al de Almadén son de la misma peña que este, y sobre unos y otros crecen las propias especies de plantas; de lo cual se infiere que la mina de cinabrio no exhala los vapores venenosos que se creen, y las exhalaciones mercuriales tampoco dañan a la vegetación ni a los hombres, pues un minero puede dormir con seguridad sobre una veta de cinabrio.

old spanish miner - 1905

Antiguo minero español. 1905

Los presidiarios que allí se envían no padecen nada en la mina, ni sufren convulsiones, como se ha creído por mucho tiempo, ni hacen otra cosa que acarrear tierra en los carretoncillos; pero suelen fingirse paralíticos algunos de ellos para mover a la piedad y estafar algo a los que van a ver aquello. Cualquiera vecino del Almadén trabaja voluntariamente más de un doble que los forzados para ganar menos de la mitad de lo que le cuesta al Rey cada uno de estos. Dos son las vetas que atraviesan la colina a lo largo y tienen de dos a catorce pies de ancho. La piedra de estas vetas es la misma que la de lo restante de la colina y sirve solo de matriz al cinabrio, que es más o menos abundante; según la piedra que le contiene es de arena más fina o más gruesa. Se hallan en ella piritas y pedazos de cuarzo blanco, ramificados ricamente de cinabrio, y también espato ligero, y a veces cristalino, lleno uno y otro de la misma materia, ya en forma de rubíes, ya en hojas. Hay también pizarras llenas de lo mismo; y el Hornstein de los mineros se ve penetrado del cinabrio como si fuera de puntas de clavos. Por fin, se ve el azogue puro y natural en las quebraduras de las pizarras y de las piedras de arenas… …Pueden producir estas minas como 20 quintales de azogue.”
Habría que volver atrás 182 años para ver si todo lo que decía era verdad.

Navajun, La Rioja, Spain. Pyrite crystals

The Navajun Mine and its world famous pyrite cubes

2- 5.7 cm

Below is an extract of the flyer written by Piritas de Navajun SL, some of the information could be outdated but still a nice text in english about the most famous pyrite cubes in the world.

1- 6cm

The Navajun Mine

The Navajun Mine that produces exclusively pyrite crystals was discovered in 1960 by miner Pedro Ansorena Garret. Currently the mining property belongs to the company Piritas de Navajun S.L. which was formed by Pedro Ansorena Conde, Jose Chaver Atanasio and Nestor Lopez Ogalde.

Pyrite is an iron sulphide known from the early days of civilization. In the ancient China was used to attract richness and prosperity, given its metallic shine. In the old days, was used by magicians and alchemists who attributed medicinal properties to the stone. According to historians, in the La Rioja region, the stones were called “Stones of Santa Casilda”and were employed as ammunition for the rubber slings used to repel the wolves.

This “Natural Phenomena” represents the only concentration of pyrites known in the world, with an awesome perfection of cubes and group crystals of large size. Cubes with edges of up to 21 centimeters have been extracted from the mine.

The perfection and beauty of the specimens, true sculptures inspiring artists and architects are exhibited in the most important mineralogical museums of the world, such as Smithsonian Institution, Washington, USA, Germany, Switzerland, France, Japan, etc.

9- 9.5 cm

The origin of the pyrites talks about the decomposition of organic material in sedimentary rocks (limestones and sandstones) in a reducing environment, which generated sulphur that reacted with the iron present in the surrounding rocks. These rocks are approximately 125 – 130 million years old and were formed under the same geological environment of the Jurassic sediments present in the La Rioja region. Fossil dinosaurs tracks are commonly found in the rocks of the region.
The size and shape variation of each crystal group, the differences between the angles of the crystallisation axis of each cube and the differential growth of the various cubes, given infinite possibilities of shapes and forms. Besides the individual cube which constitute a work of art as such each specimen is different from each other.

10- 10 cm

Due to the delicate nature of the pyrites (this mineral is hard but fragile), the extraction work is conducted by hand and each sample is prepared as an individual sculpture. Furthermore, the discovery of a mineral with unique features worldwide, is a fascinating task.

Navajun village


The beautiful village of Navajun, from which the name of the mine comes, is located in the Aguilar del Rio Alhama area and was donated in 1381 by Enrique II to the Navarran Gentile Juan Ramirez de Arellano, Senor de Cameros. The donation included the villages of Aguilar Valdemadera, two beautiful villages located in the neighbourhood of Navajun.
Currently the village keeps the same features from its construction in the XVI century, occupying 16,3 square kilometres of mountainous terrain.

Besides the Mine, the resources of the village are sheep growing and cultivation of cereals. Its population has been gradually decreasing through the last century, from 310 inhabitants in 1900 to 220 in 1950, 152 in 1970 and 22 nowadays.