Monte Amiata earth pigments and diatomaceous earth district, Tuscany, Italyi
| Regional Level Types | |
|---|---|
| Monte Amiata earth pigments and diatomaceous earth district | Mining District (Repurposed) |
| Tuscany | Region |
| Italy | Country |
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Type:
Mining District (Repurposed) - last checked 2025
Deposit first discovered:
Before 1795
Largest Settlements:
| Place | Population |
|---|---|
| Abbadia San Salvatore | 6,364 (2014) |
| Castel del Piano | 3,507 (2014) |
| Piancastagnaio | 3,158 (2014) |
| Bagnolo | 612 (2014) |
| Vivo d'Orcia | 532 (2014) |
| Bagnoli | 490 (2014) |
At the foothill of Monte Amiata volcano (southern Tuscany, Italy), small extinct lake basins of late Pleistocene age are documented. These lake basins were characterized by the deposition of two very different types of sediment: a) derived from the authigenic precipitation of iron oxides (goethite) and exploited as earth pigments; b) biogenic siliceous sediment composed of fossil diatoms and named diatomaceous earth or diatomite. The lacustrine sediments of Mount Amiata volcano were widely exploited for various applications since ancient times. Literary documents begin in the 16th century, with the descriptions of Cesalpino, Gesner, Agricola, and Imperato.
a) The deposits of clay earth pigments in the ochreous sediments of Monte Amiata were exploited for the production of two pigments known as raw sienna and burnt sienna (“Terra di Siena naturale” and “Terra di Siena bruciata” in Italian). These names evidently refer to the provenance and technological processing of the earth, but are now used for all pigments with similar tinting properties.
Widely exploited for industrial commerce in the 19 th and 20 th centuries (up to 50,000 tons of production), in contrast to other clay earth pigments, raw and burnt sienna are bright colours with a high coating efficiency. Raw sienna is generally divided into yellow earths and brown boles, plus intermediate yellow to brown bolar earths (“terre bolari” in Italian) (ref. and for more details on classifications).
b) Specific references to the diatomites of Monte Amiata are quoted in the 17th century by Boccone and Bonanno. The quarrying activity was described by Micheli in 1733. During the 18th and 19th centuries, the diatomaceous earths of Monte Amiata are part of the important geological collections of Micheli, Targioni Tozzetti, Baldassarri, Campani, and Tommi. A particular significance has the collection of botanic and ichthyologic fossils collected by Ezio Tongiorgi now preserved in the Museum of Natural History of the University of Pisa sited at the Charterhouse of Pisa in the Calci village. These paleontological samples preserve the biological and physical testimonies of the environmental and climatic changes of the late Pleistocene and are now particularly valuable because they are the only remaining evidence of the diatomaceous lacustrine deposits of the paleo-lakes of Monte Amiata. For these reasons, they represent geological materials with a fundamental cultural value.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsMineral List
Mineral list contains entries from the region specified including sub-localities2 valid minerals.
Rock Types Recorded
Note: data is currently VERY limited. Please bear with us while we work towards adding this information!
Rock list contains entries from the region specified including sub-localities
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Alphabetical List Tree DiagramGallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 4 - Oxides and Hydroxides | |||
|---|---|---|---|
| ⓘ | Goethite | 4.00. | Fe3+O(OH) |
| ⓘ | Opal | 4.DA.10 | SiO2 · nH2O |
| Unclassified | |||
| ⓘ | 'Limonite' | - | |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Goethite | Fe3+O(OH) |
| H | ⓘ Opal | SiO2 · nH2O |
| O | Oxygen | |
| O | ⓘ Goethite | Fe3+O(OH) |
| O | ⓘ Opal | SiO2 · nH2O |
| Si | Silicon | |
| Si | ⓘ Opal | SiO2 · nH2O |
| Fe | Iron | |
| Fe | ⓘ Goethite | Fe3+O(OH) |
Geochronology
Mineralization age: Pleistocene : 0.14 Ma to 0.13 MaImportant note: This table is based only on rock and mineral ages recorded on mindat.org for this locality and is not necessarily a complete representation of the geochronology, but does give an indication of possible mineralization events relevant to this locality. As more age information is added this table may expand in the future. A break in the table simply indicates a lack of data entered here, not necessarily a break in the geologic sequence. Grey background entries are from different, related, localities.
| Geologic Time | Rocks, Minerals and Events | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Phanerozoic | ||||||||||
| Cenozoic | ||||||||||
| Quaternary | ||||||||||
| Pleistocene |
| |||||||||
Fossils
There are 1 fossil locality from the PaleoBioDB database within this region.These data are provided on an experimental basis and are taken from external databases. Mindat.org has no control currently over the accuracy of these data.
| Occurrences | 1 |
|---|---|
| Youngest Fossil Listed | 5.33 Ma (Miocene) |
| Oldest Fossil Listed | 11.6 Ma (Miocene) |
| Fossils from Region | Click here to show the list. |
| Fossil Localities | Click to show 1 fossil locality |
Localities in this Region
- Tuscany
- Grosseto Province
- Arcidosso
- Castel del Piano
- Santa Fiora
- Grosseto Province
Other Regions, Features and Areas that Intersect
Eurasian PlateTectonic Plate
- Campanian ArcVolcanic Arc
Italy
- Tuscany
- Monte Amiata mercury mining districtMining District
- Orcia ValleyValley
This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to
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References
[3]Giannetti, Carlo (1873) Sulle terre gialle e bolari del Monte Amiata (Dette comunemente Terre di Siena) [About the yellow ochre and umber earth pigments of Mount Amiata (commonly called “Terre di Siena”)] - Notizie chimico industriali con appendice relativa alla Farina Fossile del Monte Amiata [Industrial chemical news with an appendix on Mount Amiata's diatomite]. Società Anonima delle Terre bolari e gialle in Siena.
[4]Guasparri, Giovanni; Farsi, Ferruccio; Ferraioli, Massimo; Donati, Gabriele - Ed. (2005) Catalogo della Collezione delle Terre Bolari naturali e manufatte del Monte Amiata [Catalogue of the Collection of Raw and Manufactured Bolar Earth Pigments of Monte Amiata]. https://www.museofisiocritici.it/terrebolari.aspCatalogue of 60 historical specimens, each with its own picture.
[2]Manasse, Andrea, Mellini, Marcello (2006) Iron (hydr)oxide nanocrystals in raw and burnt sienna pigments. European Journal of Mineralogy, 18 (6) 845-853 doi:10.1127/0935-1221/2006/0018-0845
[1]Vezzoli, Luigina; Principe, Claudia; Sorbini, Chiara (2021) The paleo-lacustrine diatomaceous deposits of Monte Amiata volcano (Tuscany, Italy) and the Ezio Tongiorgi paleontological collection in the Museum of Natural History of the University of Pisa. Annals of Geophysics, 64 (5). doi:10.4401/ag-8634
Monte Amiata earth pigments and diatomaceous earth district, Tuscany, Italy