Description: Smith (1980): "The pyrrhotite nodules vary in size from 1 mm to slightly over 4 cm in diameter. The outer surface consists of platy hexagonal crystals arranged with pinacoid faces subparallel. The crystals range from less than 0.5 mm to over 5 cm in diameter and vary in color from metallic gray to bronze, but rapidly weather to a very rusty brown on exposure. Most of the nodules react weakly to a magnet. Some do not and may actually be pseudomorphs. Rarely, isolated small groups and single microcrystals occur on thin plates of massive pyrrhotite. The interior of the nodules has a somewhat foliated structure that radiates from the center. The centers of many nodules are hollow but others are filled with intergrown, clear, tabular barite crystals. Microcrystals of barite also occur in cracks. Both occurrences of barite are of secondary origin. Tiny crystals of pyrite may occur on the pyrrhotite crystals. The smaller nodules (0.5 to 1 cm in diameter) are actually flattened rosettes that occur alone or in flat aggregates. Some of the rosettes have a crude but distinct hexagonal outline. The larger nodules (1 to 4 cm in diameter) always occur alone and are rounded. These nodules may also have a crude hexagonal outline, a circular outline, or a star-shaped outline."

ⓘ Quartz

Formula: SiO₂

Locality: Hoskins Mound Mine, Hoskins Mound, Hoskins, Brazoria County, Texas, USA

References:

Smith, Arthur E. (1991) Texas Mineral Locality Index. Rocks & Minerals, 66 (3) 196-224 doi:10.1080/00357529.1991.11761622

ⓘ Siderite

Formula: FeCO₃

Localities:

Damon Mound Salt Dome, Damon, Brazoria County, Texas, USA
Bryan Mound, Freeport, Brazoria County, Texas, USA

ⓘ Sphalerite

Formula: ZnS

Localities:

Damon Mound Salt Dome, Damon, Brazoria County, Texas, USA
Hoskins Mound Mine, Hoskins Mound, Hoskins, Brazoria County, Texas, USA

Fluorescence: Deep red

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
ⓘ	Native Sulphur	1.CC.05	S₈
Group 2 - Sulphides and Sulfosalts
ⓘ	Sphalerite	2.CB.05a	ZnS
ⓘ	Pyrrhotite	2.CC.10	Fe_1-xS
ⓘ	Galena	2.CD.10	PbS
ⓘ	Hauerite	2.EB.05a	MnS₂
ⓘ	Pyrite	2.EB.05a	FeS₂
ⓘ	Marcasite	2.EB.10a	FeS₂
Group 3 - Halides
ⓘ	Halite	3.AA.20	NaCl
ⓘ	Fluorite ?	3.AB.25	CaF₂
Group 4 - Oxides and Hydroxides
ⓘ	Quartz	4.DA.05	SiO₂
Group 5 - Nitrates and Carbonates
ⓘ	Calcite	5.AB.05	CaCO₃
ⓘ	Magnesite	5.AB.05	MgCO₃
ⓘ	Siderite	5.AB.05	FeCO₃
ⓘ	Dolomite	5.AB.10	CaMg(CO₃)₂
ⓘ	Aragonite	5.AB.15	CaCO₃
Group 7 - Sulphates, Chromates, Molybdates and Tungstates
ⓘ	Anhydrite	7.AD.30	CaSO₄
ⓘ	Baryte	7.AD.35	BaSO₄
ⓘ	Celestine	7.AD.35	SrSO₄
ⓘ	Melanterite	7.CB.35	Fe²⁺(H₂O)₆SO₄ · H₂O
ⓘ	Gypsum	7.CD.40	CaSO₄ · 2H₂O
Group 9 - Silicates
ⓘ	Danburite	9.FA.65	CaB₂Si₂O₈
Unclassified
ⓘ	'Petroleum'	-

List of minerals for each chemical element

H	Hydrogen
H	ⓘ Gypsum	CaSO₄ · 2H₂O
H	ⓘ Melanterite	Fe²⁺(H₂O)₆SO₄ · H₂O
B	Boron
B	ⓘ Danburite	CaB₂Si₂O₈
C	Carbon
C	ⓘ Aragonite	CaCO₃
C	ⓘ Calcite	CaCO₃
C	ⓘ Dolomite	CaMg(CO₃)₂
C	ⓘ Magnesite	MgCO₃
C	ⓘ Siderite	FeCO₃
O	Oxygen
O	ⓘ Anhydrite	CaSO₄
O	ⓘ Aragonite	CaCO₃
O	ⓘ Baryte	BaSO₄
O	ⓘ Calcite	CaCO₃
O	ⓘ Celestine	SrSO₄
O	ⓘ Danburite	CaB₂Si₂O₈
O	ⓘ Dolomite	CaMg(CO₃)₂
O	ⓘ Gypsum	CaSO₄ · 2H₂O
O	ⓘ Magnesite	MgCO₃
O	ⓘ Melanterite	Fe²⁺(H₂O)₆SO₄ · H₂O
O	ⓘ Quartz	SiO₂
O	ⓘ Siderite	FeCO₃
F	Fluorine
F	ⓘ Fluorite	CaF₂
Na	Sodium
Na	ⓘ Halite	NaCl
Mg	Magnesium
Mg	ⓘ Dolomite	CaMg(CO₃)₂
Mg	ⓘ Magnesite	MgCO₃
Si	Silicon
Si	ⓘ Danburite	CaB₂Si₂O₈
Si	ⓘ Quartz	SiO₂
S	Sulfur
S	ⓘ Anhydrite	CaSO₄
S	ⓘ Baryte	BaSO₄
S	ⓘ Celestine	SrSO₄
S	ⓘ Galena	PbS
S	ⓘ Gypsum	CaSO₄ · 2H₂O
S	ⓘ Hauerite	MnS₂
S	ⓘ Marcasite	FeS₂
S	ⓘ Melanterite	Fe²⁺(H₂O)₆SO₄ · H₂O
S	ⓘ Pyrite	FeS₂
S	ⓘ Pyrrhotite	Fe_1-xS
S	ⓘ Sphalerite	ZnS
S	ⓘ Native Sulphur	S₈
Cl	Chlorine
Cl	ⓘ Halite	NaCl
Ca	Calcium
Ca	ⓘ Anhydrite	CaSO₄
Ca	ⓘ Aragonite	CaCO₃
Ca	ⓘ Calcite	CaCO₃
Ca	ⓘ Danburite	CaB₂Si₂O₈
Ca	ⓘ Dolomite	CaMg(CO₃)₂
Ca	ⓘ Fluorite	CaF₂
Ca	ⓘ Gypsum	CaSO₄ · 2H₂O
Mn	Manganese
Mn	ⓘ Hauerite	MnS₂
Fe	Iron
Fe	ⓘ Marcasite	FeS₂
Fe	ⓘ Melanterite	Fe²⁺(H₂O)₆SO₄ · H₂O
Fe	ⓘ Pyrite	FeS₂
Fe	ⓘ Pyrrhotite	Fe_1-xS
Fe	ⓘ Siderite	FeCO₃
Zn	Zinc
Zn	ⓘ Sphalerite	ZnS
Sr	Strontium
Sr	ⓘ Celestine	SrSO₄
Ba	Barium
Ba	ⓘ Baryte	BaSO₄
Pb	Lead
Pb	ⓘ Galena	PbS

Fossils

There are 12 fossil localities 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

Youngest Fossil Listed

23.0 Ma (Oligocene)

Oldest Fossil Listed

28.1 Ma (Oligocene)

Stratigraphic Units

Unit	No. Occurrences	Age
Anahuac	12	28.1 - 23.03 Ma (Cenozoic)

Fossils from Region

Click here to show the list.

Accepted Name	Hierarchy	Age
Chlamys genus	Animalia : Mollusca : Bivalvia : Pectinida : Pectinidae : *Chlamys*	28.1 - 23.03 Ma Cenozoic
Prionocidaris genus	Animalia : Echinodermata : Echinoidea : Cidaroida : Cidaridae : *Prionocidaris*	28.1 - 23.03 Ma Cenozoic
Brissus genus	Animalia : Echinodermata : Echinoidea : Spatangoida : Brissidae : *Brissus*	28.1 - 23.03 Ma Cenozoic
Antiguastrea cellulosa species	Animalia : Cnidaria : Anthozoa : Scleractinia : Faviidae : Antiguastrea : *Antiguastrea cellulosa*	28.1 - 23.03 Ma Cenozoic
Kuphus genus	Animalia : Mollusca : Bivalvia : Myida : Teredinidae : *Kuphus*	28.1 - 23.03 Ma Cenozoic
Porites douvillei species	Animalia : Cnidaria : Anthozoa : Scleractinia : Poritidae : Porites : *Porites douvillei*	28.1 - 23.03 Ma Cenozoic
Montastrea intermedia species	Animalia : Cnidaria : Anthozoa : Scleractinia : Montastraeidae : Montastraea : *Montastrea intermedia*	28.1 - 23.03 Ma Cenozoic
Ellipsechinus prisca species	Animalia : Echinodermata : Echinoidea : Echinoida : Ellipsechinus : *Ellipsechinus prisca*	28.1 - 23.03 Ma Cenozoic
Agassizia (Anisaster) mossomi species	Animalia : Echinodermata : Echinoidea : Spatangoida : Schizasteridae : Anisaster : *Agassizia (Anisaster) mossomi*	28.1 - 23.03 Ma Cenozoic
Clypeaster rogersi species	Animalia : Echinodermata : Echinoidea : Clypeasteroida : Clypeasteridae : Clypeaster : *Clypeaster rogersi*	28.1 - 23.03 Ma Cenozoic
Clypeaster oxybaphon species	Animalia : Echinodermata : Echinoidea : Clypeasteroida : Clypeasteridae : Clypeaster : *Clypeaster oxybaphon*	28.1 - 23.03 Ma Cenozoic
Lovenia alabamensis species	Animalia : Echinodermata : Echinoidea : Spatangoida : Loveniidae : Lovenia : *Lovenia alabamensis*	28.1 - 23.03 Ma Cenozoic

Fossil Localities

Click to show 1 fossil locality

USA

Texas
- Brazoria County
  - Cenozoic🐚 Damon Mound

Other Databases

Wikipedia:	https://en.wikipedia.org/wiki/Brazoria_County,_Texas
Wikidata ID:	Q27034
GeoNames ID:	4676137

Localities in this Region

Other Regions, Features and Areas that Intersect

North AmericaContinent

North America PlateTectonic Plate

Gulf of Mexico BasinBasin
Northern Gulf of Mexico MarginPassive Margin
Sabine DomainDomain

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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