Ferberita

Description

Square piece with a black crest. Not a block: readable individuals—complete prisms with perfect terminations in alternating arrangement. A line of calcite crowns it and a froth of siderite coats it. Superb architecture.

History of this specimen

First seen months earlier on Mindat and later recognised, almost by intuition, when it reappeared for sale on eBay. On both occasions it was its straight-lined architecture and its snow-capped "Cresta Montis" that caught my attention. It came from Quebul Fine Minerals (MinID JFY-5CN / Photo ID 647803) and later belonged to Cyril Grangeon. At some point in transit it lost a small fragment of calcite at the upper left, without affecting the composition or visual balance. Mindat entry: https://www.mindat.org/photo-647803.html

About Ferberita

Ferberite is a wolframite, because wolframite is not a single species but a continuous solid-solution series from the iron-rich end-member, ferberite (FeWO₄), to the manganese-rich end-member, hübnerite (MnWO₄). Its name comes from a medieval mining metaphor: to Saxon smelters it was the Wolf Rahm ("wolf’s foam"), because it ate their precious tin like a wolf eats sheep. And although the Spanish Elhuyar brothers isolated the element in 1783 and gave it the symbol W, in the English-speaking world the name tungsten (from the Swedish "heavy stone") prevailed. Tungsten proved to be a metal with very particular properties: the highest melting point, 3,550°, and marked hardness. During the Second World War Germany knew how to apply it to machinery and armaments: impenetrable armour and gun barrels that did not overheat. The Allies simply put it into lamp filaments; they had the money but not the technique: they did not know how to exploit its properties.

About the locality

Panasqueira is a classic deposit on the Iberian Peninsula, known for its quartz but with a past tied to the 20th-century wars: together with the deposits of El Bierzo it forms the peninsula’s wolfram axis. Its importance lies in the fact that during the Second World War it became the "black gold" of the area: a strategic resource that the Germans paid well for, and that the Americans paid even better for, solely to keep it out of Nazi hands. The Allies even threw entire ships loaded with wolfram into the sea because they did not know how to exploit it. It was a time of contrasts and misery. While at Panasqueira, under British supervision, ore was mined industrially by the tonne (the workforce rose from 750 workers in 1933 to c. 5,800 in 1943), on the slopes of El Bierzo it was torn out by any means, seeking to escape poverty and hunger, mixing strokes of luck with some exploitation and considerable violence. Portugal, a neutral, small country with a key resource, sold to both sides. Neither hero nor traitor, it tried to survive between huge powers to avoid being crushed by either side. That is in the past. Over time, and in the 21st century, the paragenetic beauty of the hydrothermal veins of this Portuguese mine has prevailed over the war memory. Its aesthetic and mineralogical richness came fully to the fore in the 2000s with the rise of digital photography, consolidating these pieces as cult objects for a new generation of collectors.

Technical data

Catalogue No.

0043

Composition

FeWO₄

Name

Ferberita

Group

Wolframatos

Category

Cresta Montis

Associations

siderita arsenopirita calcita

Mine

Minas da Panasqueira

District / Municipality

Aldeia de S. Francisco

Province

Covilhã

Region

Castelo Branco

Country

Portugal

Size (cm)

4.5 x 2.5 x 4

Weight

55.4 g

Acquired

2014

Ex-collection

Nadya Georgieva (Quebul Fine Minerals) > Cyril Grangeon

Etymology

Named in honour of Moritz Rudolph Ferber (1805–1875), a German chemist who studied tungsten minerals.

Quality

Top

Value trend

Al alza

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