Ópalo Hialita
Ópalo is a mineral with formula SiO₂·nH₂O, in the Óxidos group. This specimen comes from Mina Aurora, Charcas, San Luis Potosí, México and joined the Terrium collection in 2025.
Description
Translucent botryoidal aggregate with an open vulva-like form and a pearly centre. The piece presents a central cavity of unequivocally organic outline with smooth contours. Its vitreous texture accentuates an impression of moisture, openness and tension. Geological and symbolic at once—a natural sculpture charged with primary forms.
History of this specimen
Manual cleaning revealed a surprising central organic form: a nacreous or fleshy pearl. One of the most suggestive and sculptural pieces in my collection.
About Ópalo
Although commonly included in mineral catalogues, opal is not a true mineral but a mineraloid: it lacks a defined crystalline structure. It is hydrated silica (SiO₂·nH₂O) deposited in low-temperature environments, often in cavities of volcanic rocks. The hyalite variety is amorphous, vitreous, and shows a gelatinous or pearly aspect. Its green fluorescence under UV light is typical and much valued.
About the locality
Part of a classic opal district, Mina Aurora is known for hyalite specimens with pronounced fluorescence. It is not in regular operation today, and well-formed pieces are increasingly scarce.
Technical data
- Catalogue No.
- 0046
- Composition
- SiO₂·nH₂O
- Name
- Ópalo
- Variety
- Hialita
- Group
- Óxidos
- Category
- Cavella
- Matrix
- Roca volcánica
- Mine
- Mina Aurora
- District / Municipality
- Charcas
- Province
- San Luis Potosí
- Country
- México
- Size (cm)
- 108 x 60 x 35
- Weight
- 205 g
- Acquired
- 2025
- Etymology
- From the Greek "opallios", in turn from Sanskrit "úpala", meaning precious stone. The variety "hyalite" derives from Greek "hyalos" (glass), in allusion to its characteristic translucent, vitreous aspect.
- Quality
- Buena
- Value trend
- Estable