Jacinto de Compostela
Cuarzo is a mineral with formula SiO₂, in the Silicatos group. This specimen comes from CV-35 (km 58), Domeño, Valencia, Comunidad Valenciana, España.
Description
Opaque red Herkimer-type prism, well proportioned and of good size; thick-set.
About Cuarzo
In Spanish mineralogical literature, the name "jacinto de Compostela" is traditionally and exclusively reserved for the red variety of authigenic "floating" quartz. Although it was once thought that its colour was due to haematite, it has been determined that the red tone arises mainly from inclusions of clay minerals (Gil Marco, J., 2013). They occur in two forms—isolated doubly terminated crystals or spheroidal "hedgehog" aggregates—and characteristically appear as "floaters" embedded in marls or trapped in gypsum masses; an origin with a humble, popular, sedimentary history where, while not rare in the strict sense, quality specimens are scarce, and compact, aesthetic, doubly terminated pieces are even harder to see.
About the locality
Domeño, in the province of Valencia, forms part of a series of Triassic outcrops historically rich in gypsum and ferruginous sediments. It is in these environments that the Jacintos de Compostela crystallise, embedded in Keuper clays and gypsum. Although the term has been used in other localities (such as Aragon or La Rioja), Domeño has gained renown for the quality and sharpness of its crystals. Workings were mainly artisanal and sporadic, often carried out by collectors or local prospectors. Today, many classic areas are exhausted or protected, which has increased the historical and mineralogical value of older specimens like this.
Technical data
- Catalogue No.
- 0355
- Composition
- SiO₂
- Name
- Cuarzo
- Variety
- Jacinto de Compostela
- Group
- Silicatos
- Category
- Meritum Persé
- Mine
- CV-35 (km 58)
- District / Municipality
- Domeño
- Province
- Valencia
- Region
- Comunidad Valenciana
- Country
- España
- Etymology
- Modern mineralogical tradition explains the name by the supposed custom of pilgrims carrying them as talismans or amulets; there is no direct documented historical evidence (no medieval texts).
- Quality
- Notable
- Value trend
- Estable
Related specimens
- Abellaíta — España
- Abernathyita — España
- Abernathyita — España
- Abernathyita — España
- Aerenita — España
- Aerinita (fibrosa) — España
- Analcima — España
- Analcima — España