TERRIUM — A mineralogy cabinet


Carborundo Carburo de silicio

Carborundo Carburo de silicio is a mineral with formula SiC, in the Material sintético group. This specimen comes from Fábrica de Carborundo, Beteta, Cuenca, Castilla-La Mancha, España and joined the Terrium collection in 2025.

Carborundo 
Carburo de silicio from Fábrica de Carborundo, Beteta, Cuenca, Castilla-La Mancha, España — Terrium

Description

Laminar, crested aggregate of synthetic silicon carbide with intense rainbow iridescence (blues, violets, greens and golds) and metallic lustre; a piece of strong sculptural presence, without matrix.

History of this specimen

A worker at the Beteta (Cuenca) factory, near Solán de Cabras, gave it to me by a stroke of luck. I had a fine bluish piece, but I lent it to my friend Pedro Pantaleón for some macro videos and decided to give it to him. The next day, travelling with Óscar from Málaga to Hombrados, we stopped in Beteta and asked about an enormous, unusual factory we saw. It turned out to be the one that supplied carborundum to all Spain. There, a neighbour who had worked in it all his life listened to my story, watched the video of my original piece and gave me two excellent specimens he had kept at home for 30 years, while telling me about the rise and fall of the foundry.

About Carborundo Carburo de silicio

Although it is not recognised as an official mineral by the IMA because it is artificial, this material (known as carborundum) has always had a particular appeal. It is produced by the Acheson process, fusing silica sand and coke at over 2000 °C. The conspicuous surface colour layers are achieved by quenching the material with cold water as it comes out of the furnace, which generates a thin oxide film (similar to what occurs with goethite).

About the locality

For decades the Beteta plant was the only silicon carbide factory in the Iberian Peninsula, noted for the high quality of its output. Activity declined due to competition from large-scale Chinese imports and it closed permanently after the pandemic. These pieces are genuine witnesses to our industrial history.

Technical data

Catalogue No.
0639
Composition
SiC
Name
Carborundo Carburo de silicio
Group
Material sintético
Category
Meritum Persé
Mine
Fábrica de Carborundo
District / Municipality
Beteta
Province
Cuenca
Region
Castilla-La Mancha
Country
España
Size (cm)
5.5 x 3 x 3
Weight
47.7 g
Acquired
2025
Etymology
From the English "carborundum", a trade name coined by Edward Acheson in 1893 for synthetic silicon carbide.
Quality
Muy buena
Value trend
Estable

Related specimens

← Back to Terrium catalogue