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Foggintor Quarry, Princetown, Dartmoor Forest, West Devon, Devon, England, UKi
Regional Level Types
Foggintor QuarryQuarry
Dartmoor ForestCivil Parish
West Devon- not defined -
EnglandConstituent Country

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Latitude & Longitude (WGS84):
50° 32' 36'' North , 4° 1' 24'' West
Latitude & Longitude (decimal):
Locality type:
Köppen climate type:
Nearest Settlements:
Princetown1,366 (2018)2.5km
Dousland833 (2018)5.6km
Horrabridge3,728 (2018)6.7km
Yelverton3,627 (2018)7.1km
Tavistock12,280 (2018)8.5km
Other/historical names associated with this locality:
"Yellowmeade Quarry"

This is a partially flooded (disused) granite quarry in the central part of the Dartmoor pluton, accompanied by extensive finger dumps of waste granite.

A single, significant uraniferous vein cuts across the granite partially filling a single, continuous joint of between 1mm and 12mm thickness. Other parts of the granite also contain pockets of mineralisation. The dumps and quarry litter are significantly more accessible than the quarry faces.

Zones of the granite containing many tiny miarolitic pockets and fine black-filled fractures exhibit both primary and secondary mineralisation.

The pockets contain, amongst others, dark tourmalines, and the black veins are likewise primarily massive tourmaline. The tourmaline-lined pockets may be considered diagnostic of potential rare-element mineralisation.

In these zones may be observed the complete gamut of local species.

The quarry is very similar in geology and mineralogy to the nearby Merrivale Quarry.

Of particular note is the range of fluorescent species at this location which includes uranium minerals and some feldspars. A special caution to UV prospectors is that many of the local lichens are UV reactive (generally yellow-white or pale pink), which includes at least one with a pale blue fluorescence.

The quarry boasts a rich flora and fauna as well as considerable scope for recreational activities. This is an area rich in industrial archaeological features as well as ancient, pre-industrial sites.

The whole site is within the Dartmoor National Park, and removal of material by the public is prohibited.

Public access is by the track from the public highway, about half way between Rundlestone and Merrivale, and past Yellowmeade Farm.; There are two entrances to the quarry - the northerly one accesses the flooded northern section and the southerly accesses the occasionally flooded southern section.

Particular caution is advised to visitors to this site as the footing is more than usually hazardous in some areas, and particularly so on the faces of the dumps.

Regions containing this locality

Eurasian PlateTectonic Plate
British IslesGroup of Islands
Devon and Cornwall metalliferous mining district, England, UKMining District
Dartmoor National Park, Devon, England, UKNational Park

Select Mineral List Type

Standard Detailed Strunz Dana Chemical Elements

Mineral List

12 valid minerals.

Rock Types Recorded

Note: this is a very new system on mindat.org and data is currently VERY limited. Please bear with us while we work towards adding this information!

Select Rock List Type

Alphabetical List Tree Diagram

Detailed Mineral List:

Formula: Na2Ca(UO2)(CO3)3 · 6H2O
Habit: Distorted rhombohedra, indistinct; also massive, encrusting
Colour: Yellowish
Fluorescence: Reacts strongly to Long Wave UV light, emitting a diagnostic bluish-green.
Description: Sparse, microscopic grains scattered across weathered surfaces associated with other fluorescent material. Visible as tiny points of blue-green fluorescence under Long Wave UV. Only observable at x45 and above.
Reference: Alysson Rowan Collection
Formula: Ca(UO2)2(PO4)2 · 11H2O
Habit: Tabular, highly metamict; encrusting
Colour: Pale, dull green to greenish yellow
Fluorescence: Rects strongly under Long Wave UV light with characteristic yellowish green.
Description: Dull green to yellow metamict crystal groups found on weathered granite surfaces, also crustiform coatings. Crystals to 0.5mm
Reference: Alysson Rowan Collection
Bassetite ?
Formula: Fe2+(UO2)2(PO4)2 · 10H2O
Habit: Somewhat earthy in appearance
Colour: dun-coloured
Fluorescence: none
Description: Inferred presence of Bassetite comes from the presence of a non-fluorescent, dun-coloured, earthy encrustation in direct contact with uraninite and weathered pyrite grains in the granite.
Reference: Alysson Rowan Collection
Becquerelite ?
Formula: Ca(UO2)6O4(OH)6 · 8H2O
Habit: Indeterminate - semi-crustose.
Colour: brownish-yellow, appears very pale due to size of crystals.
Fluorescence: Reacts under Long Wave UV: dim brownish orange
Description: Appears as sparse, somewhat earthy encrustations of miniscule, brownish-yellow crystals on more exposed and weathered surfaces. As with other uranium minerals, this is associated with the weathering of uraninite in the granite. Crystals are transparent and sufficiently small to give the impression of a pale colouration at moderate magnification (x45).
Reference: Alysson Rowan Collection Robbins, M. The collector's book of fluorescent minerals. ISBN 978-1-4757-4794-2 DOI 10.1007/978-1-4757-4792-8
Formula: (K,Na)(UO2)(SiO3OH) · 1.5H2O
Habit: Radial acicular groups to ~0.3mm across; also earthy, encrusting.
Colour: Yellowish-brown to dull orange
Fluorescence: Reacts weakly under Long Wave UV, emitting a dull brownish colour.
Description: Minute earthy crusts in miarolitic cavities associated with uraninite, also with gummite crusts.
Reference: Alysson Rowan Collection
Formula: CaF2
Habit: cubic; compact and irregular
Colour: White, purple to almost black
Fluorescence: Barest hint of purple fluorescence under Long Wave UV
Description: Compact masses partially filling cracks in the granite, associated with tourmaline veins and miarolitic cavities. Material has been observed to form crystals about 5mm across, crystal faces rare. Colour varies between white and purple, sometimes almost to purple-black where associated with smoky quartz and radioactive residues. Colours are zoned in many crystals.
Reference: Alysson Rowan Collection
Habit: Massive
Colour: Brownish - may be mistaken for iron-stains.
Description: Brown haloes associated with uraninite, often dusted with Saléeite.
Reference: Alysson Rowan Collection
Formula: Ca(UO2)2(PO4)2 · 6-8H2O
Habit: Tabular, highly metamict; encrusting
Colour: Pale, dull green to greenish yellow
Fluorescence: Rects strongly under Long Wave UV light with characteristic yellowish green.
Description: Dull green to yellow metamict crystal groups found on weathered granite surfaces, also crustiform coatings. Crystals to 0.5mm
Reference: Alysson Rowan Collection
Formula: SiO2
Habit: Prismatic, hemihedral at best.
Colour: Pale; transparent to opaque white
Description: Small crystals of pale quartz may be observed within miarolytic cavities within the granite.
Reference: Alysson Rowan Collection
Quartz var: Smoky Quartz
Formula: SiO2
Habit: Prismatic to 2.5mm across. Terminations rare.
Colour: Dark brown; grey; almost black
Description: Protruding into or traversing miarolitic pockets in tourmaline veins in the granite, these dark quartz crystals are associated with some traces of radioactive residues. They are minerallogically significant only in being indicative of high levels of uranium mineralisation at some earlier time.
Reference: Alysson Rowan Collection
Formula: Mg(UO2)2(PO4)2 · 10H2O
Habit: Tabular; crustiform
Colour: Lemon yellow
Fluorescence: Brilliant yellow reaction under Long Wave UV. Some yellow reaction under blue (LED) light.
Description: Minute crystals and crusts on surfaces within recent cracks in miarolitic granite, also within some miarolitic voids. Associated with uraninite and gummite.
Reference: Alysson Rowan Collection
Formula: Cu(UO2)2(PO4)2 · 12H2O
Habit: tabular
Colour: Green.
Fluorescence: none
Description: Occasional tabular crystals associated with other uranium minerals, also as fine encrustations. Tabular crystals are typical for the species.
Reference: Alysson Rowan Collection
Formula: A(D3)G6(Si6O18)(BO3)3X3Z
Habit: Prismatic, filiform; sheaf-like growths; compact and massive
Colour: pale olive green; greenish-brown; brown to black; black
Description: While black tourmalines are common in the Dartmoor Granite, euhedral tourmaline crystals are not. The miarolitic pockets within the granite are almost invariably lined with dark tourmaline crystals - seen as parallel growths, hair-fine single crystals and sheaves. The cavities are rarely larger than a few millimetres across, and the tourmalines are scaled to suit. This type of late-stage tourmaline development is considered an indicator of potential rare-element mineralisation.
Reference: Alysson Rowan Collection
Formula: UO2
Habit: Irregular, granular; massive
Colour: Black, brownish-black
Description: Minute grains (to about 1.5mm)disseminated through miarolytic granite, often included within feldspar crystals. A small, metamict halo surrounding the grains is diagnostic. Where broken, the uraninite gives rise to a halo of brownish stain (gummite) and other secondary minerals (saléeite, probably uranophane and possibly autunite etc.) Also, massive in the single, visible vein within the quarry itself.
Reference: Alysson Rowan Collection
Formula: Ca(UO2)2(SiO3OH)2 · 5H2O
Habit: Massive
Colour: Brilliant lemon yellow.
Fluorescence: Not fluorescent under UV light.
Description: Minute crusts of lemon yellow, massive uranophane in cavities in tourmalinised granite. Only observed at the foot of the dumps.
Reference: Alysson Rowan Collection

List of minerals arranged by Strunz 10th Edition classification

Group 3 - Halides
Group 4 - Oxides and Hydroxides
Becquerelite ?4.GB.10Ca(UO2)6O4(OH)6 · 8H2O
var: Smoky Quartz4.DA.05SiO2
Group 5 - Nitrates and Carbonates
Andersonite5.ED.30Na2Ca(UO2)(CO3)3 · 6H2O
Group 8 - Phosphates, Arsenates and Vanadates
Autunite8.EB.05Ca(UO2)2(PO4)2 · 11H2O
Bassetite ?8.EB.10Fe2+(UO2)2(PO4)2 · 10H2O
Meta-autunite8.EB.10Ca(UO2)2(PO4)2 · 6-8H2O
Saléeite8.EB.05Mg(UO2)2(PO4)2 · 10H2O
Torbernite8.EB.05Cu(UO2)2(PO4)2 · 12H2O
Group 9 - Silicates
Boltwoodite9.AK.15(K,Na)(UO2)(SiO3OH) · 1.5H2O
Uranophane9.AK.15Ca(UO2)2(SiO3OH)2 · 5H2O
Unclassified Minerals, Rocks, etc.

List of minerals arranged by Dana 8th Edition classification

Becquerelite ? · 8H2O
AmBn(XO3)p·xH2O, with (m+n):p > 1:1
Andersonite15.2.5.1Na2Ca(UO2)(CO3)3 · 6H2O
AB2(XO4)2·xH2O, containing (UO2)2+
Autunite40.2a.1.1Ca(UO2)2(PO4)2 · 11H2O
Bassetite ?40.2a.16.1Fe2+(UO2)2(PO4)2 · 10H2O
Meta-autunite40.2a.1.2Ca(UO2)2(PO4)2 · 6-8H2O
Saléeite40.2a.11.1Mg(UO2)2(PO4)2 · 10H2O
Torbernite40.2a.13.1Cu(UO2)2(PO4)2 · 12H2O
Group 53 - NESOSILICATES Insular SiO4 Groups and Other Anions or Complex Cations
Insular SiO4 Groups and Other Anions of Complex Cations with (UO2)
Boltwoodite53.3.1.5(K,Na)(UO2)(SiO3OH) · 1.5H2O
Uranophane53.3.1.2Ca(UO2)2(SiO3OH)2 · 5H2O
Group 75 - TECTOSILICATES Si Tetrahedral Frameworks
Si Tetrahedral Frameworks - SiO2 with [4] coordinated Si
Unclassified Minerals, Mixtures, etc.
var: Smoky Quartz

List of minerals for each chemical element

H SaléeiteMg(UO2)2(PO4)2 · 10H2O
H UranophaneCa(UO2)2(SiO3OH)2 · 5H2O
H AutuniteCa(UO2)2(PO4)2 · 11H2O
H TorberniteCu(UO2)2(PO4)2 · 12H2O
H Meta-autuniteCa(UO2)2(PO4)2 · 6-8H2O
H AndersoniteNa2Ca(UO2)(CO3)3 · 6H2O
H Boltwoodite(K,Na)(UO2)(SiO3OH) · 1.5H2O
H BecquereliteCa(UO2)6O4(OH)6 · 8H2O
H BassetiteFe2+(UO2)2(PO4)2 · 10H2O
B TourmalineA(D3)G6(Si6O18)(BO3)3X3Z
C AndersoniteNa2Ca(UO2)(CO3)3 · 6H2O
O UraniniteUO2
O TourmalineA(D3)G6(Si6O18)(BO3)3X3Z
O SaléeiteMg(UO2)2(PO4)2 · 10H2O
O Quartz (var: Smoky Quartz)SiO2
O UranophaneCa(UO2)2(SiO3OH)2 · 5H2O
O AutuniteCa(UO2)2(PO4)2 · 11H2O
O TorberniteCu(UO2)2(PO4)2 · 12H2O
O Meta-autuniteCa(UO2)2(PO4)2 · 6-8H2O
O AndersoniteNa2Ca(UO2)(CO3)3 · 6H2O
O Boltwoodite(K,Na)(UO2)(SiO3OH) · 1.5H2O
O QuartzSiO2
O BecquereliteCa(UO2)6O4(OH)6 · 8H2O
O BassetiteFe2+(UO2)2(PO4)2 · 10H2O
F FluoriteCaF2
Na AndersoniteNa2Ca(UO2)(CO3)3 · 6H2O
Na Boltwoodite(K,Na)(UO2)(SiO3OH) · 1.5H2O
Mg SaléeiteMg(UO2)2(PO4)2 · 10H2O
Si TourmalineA(D3)G6(Si6O18)(BO3)3X3Z
Si Quartz (var: Smoky Quartz)SiO2
Si UranophaneCa(UO2)2(SiO3OH)2 · 5H2O
Si Boltwoodite(K,Na)(UO2)(SiO3OH) · 1.5H2O
Si QuartzSiO2
P SaléeiteMg(UO2)2(PO4)2 · 10H2O
P AutuniteCa(UO2)2(PO4)2 · 11H2O
P TorberniteCu(UO2)2(PO4)2 · 12H2O
P Meta-autuniteCa(UO2)2(PO4)2 · 6-8H2O
P BassetiteFe2+(UO2)2(PO4)2 · 10H2O
K Boltwoodite(K,Na)(UO2)(SiO3OH) · 1.5H2O
Ca FluoriteCaF2
Ca UranophaneCa(UO2)2(SiO3OH)2 · 5H2O
Ca AutuniteCa(UO2)2(PO4)2 · 11H2O
Ca Meta-autuniteCa(UO2)2(PO4)2 · 6-8H2O
Ca AndersoniteNa2Ca(UO2)(CO3)3 · 6H2O
Ca BecquereliteCa(UO2)6O4(OH)6 · 8H2O
Fe BassetiteFe2+(UO2)2(PO4)2 · 10H2O
Cu TorberniteCu(UO2)2(PO4)2 · 12H2O
U UraniniteUO2
U SaléeiteMg(UO2)2(PO4)2 · 10H2O
U UranophaneCa(UO2)2(SiO3OH)2 · 5H2O
U AutuniteCa(UO2)2(PO4)2 · 11H2O
U TorberniteCu(UO2)2(PO4)2 · 12H2O
U Meta-autuniteCa(UO2)2(PO4)2 · 6-8H2O
U AndersoniteNa2Ca(UO2)(CO3)3 · 6H2O
U Boltwoodite(K,Na)(UO2)(SiO3OH) · 1.5H2O
U BecquereliteCa(UO2)6O4(OH)6 · 8H2O
U BassetiteFe2+(UO2)2(PO4)2 · 10H2O

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org

251.902 - 298.9 Ma

ID: 3193041
Paleozoic intrusive rocks

Age: Phanerozoic (251.902 - 298.9 Ma)

Lithology: Intrusive igneous rocks

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

Permian - Carboniferous
251.902 - 358.9 Ma

ID: 2027408
Unnamed Igneous Intrusion, Carboniferous To Permian

Age: Phanerozoic (251.902 - 358.9 Ma)

Lithology: Felsic-rock

Reference: British Geological Survey. DiGMapGB-625. British Geological Survey ©NERC. [23]

443.8 - 485.4 Ma

ID: 3154416
Ordovician granite

Age: Ordovician (443.8 - 485.4 Ma)

Lithology: Granite group

Reference: Asch, K. The 1:5M International Geological Map of Europe and Adjacent Areas: Development and Implementation of a GIS-enabled Concept. Geologisches Jahrbuch, SA 3. [147]

Data and map coding provided by Macrostrat.org, used under Creative Commons Attribution 4.0 License


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Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Manuel A. Robbins, The Collector’s Book of Fluorescent Minerals, 1st ed. Springer US, 1983.

External Links

http://www.fluomin.org/uk/accueil.php - Online Database of Luminescent minerals

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 visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.
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