TERRIUM — A mineralogy cabinet

Fluorita Azul

Fluorita is a mineral with formula CaF₂, in the Haluros group. This specimen comes from Galería 49 de Mina Viesca, Huergo, La Collada, Asturias, España and joined the Terrium collection in 2010.

Fluorita Azul from Galería 49 de Mina Viesca, Huergo, La Collada, Asturias, España — Terrium

Description

Large blue fluorite in cubic crystals. Well-defined stepped intergrowth (the typical mosaic habit) with matte faces. Gem quality. Complete and stable; representative of the classic cubic habit with homogeneous sky-blue colour. A high-quality Spanish classic.

History of this specimen

This is the piece that Óscar and I bought at the Madrid show almost twenty years ago. On the last day, almost at the last minute. I had never seen fluorite, or at least I was not aware I had. The sky-blue colour and the geometry of the cubes caught my eye, but I did not know it was a piece from the Iberian Peninsula. We have looked after it very carefully. Because we love it. As a small extra: The specimen comes from material that Fernando Brugos, former holder of the La Viesca concession, gathered over years.

About Fluorita

First the mineral, then the element. Fluorite is a halide (calcium fluoride) that crystallises in the cubic system. The element fluorine takes its name from this mineral; it is so reactive that isolating it posed a very dangerous challenge to nineteenth-century chemistry, costing the health and lives of the so-called "martyrs of fluorine". Only in 1886 did Henri Moissan finally isolate it by electrolysis as a pale yellow gas—an achievement that earned him the 1906 Nobel Prize in Chemistry.

About the locality

Gallery 49, from which this specimen came, was opened in 2009 and produced blue specimens with fluorite cubes of good size. The mines stood idle for a long time until operations restarted in 2004 via an inclined ramp of c. 5 km. Although the original concession for La Viesca was for coal, what is actually produced is fluorite. The fluorite crystals are predominantly cubic, with colours from colourless to deep violet. The major world mineralogical milestone came in 2010 with the discovery of the celebrated "Geoda de Las Monjas", which produced about 400 exceptional specimens, including a beast measuring 70×70 and 135 kg. The best historical compilation is at https://www.foro-minerales.com/forum/viewtopic.php?t=5934

Technical data

Catalogue No.
0138
Composition
CaF₂
Name
Fluorita
Variety
Azul
Group
Haluros
Category
Lucimera
Mine
Galería 49 de Mina Viesca
District / Municipality
Huergo
Province
La Collada
Region
Asturias
Country
España
Size (cm)
8 x 8 x 6
Weight
483 g
Acquired
2010
Etymology
From the Latin "fluere", 'to flow', in reference to its historical use in metallurgy as a flux.
Quality
Top
Value trend
Al alza

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