Szczegóły publikacji
Opis bibliograficzny
Agates from Sidi Rahal, in the Atlas Mountains of Morocco: gemological characteristics and proposed origin / Magdalena DUMAŃSKA-SŁOWIK, Lucyna NATKANIEC-NOWAK, Aleksandra Wesełucha-Birczyńska, Adam GAWEŁ, Marek LANKOSZ, Paweł WRÓBEL // Gems & Gemology ; ISSN 0016-626X. — 2013 — vol. 49 no. 3, s. 148–159. — Bibliogr. s. 158–159
Autorzy (6)
- AGHDumańska-Słowik Magdalena
- AGHNatkaniec-Nowak Lucyna
- Wesełucha-Birczyńska Aleksandra
- AGHGaweł Adam
- AGHLankosz Marek
- AGHWróbel Paweł
Dane bibliometryczne
| ID BaDAP | 78688 |
|---|---|
| Data dodania do BaDAP | 2014-01-16 |
| DOI | 10.5741/GEMS.49.3.148 |
| Rok publikacji | 2013 |
| Typ publikacji | artykuł w czasopiśmie |
| Otwarty dostęp |  |
| Czasopismo/seria | Gems & Gemology |
Abstract
Moroccan agates from Sidi Rahal occur within Triassic basaltoids as lens-shaped specimens in sizes up to 25 cm. Their coloration and internal structure are quite specific and characteristic for this region. The pink outer rim is composed of opal-CT. The layer within it, usually red or red-brown, contains a significant concentration of Fe compounds (hematite and goethite) that are responsible for this zone's color. The nodules' interior, usually blue-gray or white-gray, is formed of fibrous low-a quartz (a low-temperature polymorph of quartz) with minor amounts of moganite. The presence of moganite and Fe compound inclusions suggests that the agate's formation was induced by Fe3+ activity in silica-rich fluids. Other solid inclusions such as Cu sulfides, Ti oxides, calcite, and an organic substance were incorporated during post-magmatic, hydrothermal, or hypogenic conditions.
