TERRIUM — A mineralogy cabinet


Ópalo Menilito

Ópalo is a mineral with formula SiO₂·nH₂O, in the Mineraloides (Óxidos) group. This specimen comes from Embalse de Camarillas, Agramón, Hellín, Albacete, Castilla-La Mancha, España and joined the Terrium collection in 2024.

Ópalo Menilito from Embalse de Camarillas, Agramón, Hellín, Albacete, Castilla-La Mancha, España — Terrium

Description

Mammilliform nodule with basal folds. Nature is capricious.

About Ópalo

A non-precious opal variety of sedimentary origin, formed by silica accumulation in lacustrine and diagenetic settings, producing compact botryoidal forms. Its rounded shapes often resemble human or animal figures; in the area they have historically been called "idolillos". It is said that in prehistory they were used in rituals or as amulets.

About the locality

The abundance of this whitish, dull opal in the Embalse de Camarillas area is due to ancient lakes populated by diatoms, microscopic algae with silica skeletons that, on dying, formed layers of white mud (diatomite). This material dissolved and resolidified into these typical nodular forms.

Technical data

Catalogue No.
0398
Composition
SiO₂·nH₂O
Name
Ópalo
Variety
Menilito
Group
Mineraloides (Óxidos)
Category
Meritum Persé
Matrix
Caliza
Mine
Embalse de Camarillas
District / Municipality
Agramón, Hellín
Province
Albacete
Region
Castilla-La Mancha
Country
España
Acquired
2024
Etymology
From Sanskrit upala, meaning precious stone. But 'menilite' is a toponym, referring to the place of its original discovery, Ménilmontant, a district of Paris.
Quality
Muy buena
Value trend
Estable

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