Composition and occurence of salt minerals in Death Valley

Mineral

Composition

Known or probable occurrence

Halite

NaCl

Principal constituent of chloride zone and of salt-impregnated sulfate and carbonate deposits.

SyIvite

KCI

With halite.

Nahcolite

NaHCO₃

Not yet identified; might be found in wintertime as efflorescence or trona or thermonatrite in carbonate zone in Cottonball Basin.

Trona

Na₃H(CO₃)₂2H₂O

Carbonate zone of Cottonball Basin, especially in marshes.

Thermonatrite

Na₂CO₃·H₂O

Questionably present on floodplain in Badwater Basin, would be expected in marshes of carbonate zone in Cottonball Basin.

Natron

Na₂CO₃·10H₂O

Not yet identified but may be expected, especially In winter, immediately following rains or periods of high discharge at marshes in carbonate zone in Cottonball Basin.

Pirssonite

Na₂Ca(CO₃)2·2H₂O

Not yet identified, may be expected in environments where gaylussite would be dehydrated.

Gaylussite

Na₂Ca(CO₃)2·5H₂O

Carbonate zone and floodplain in Badwater Basin.

Calcite

CaCO₃

Occurs as clastic grains in sediments underlying salt pan and as sharply terminated crystals in clay fraction of carbonate zone and in sediments underlying sulfate zone.

Magnesite

MgCO₃

Obtained in artificially evaporated brines from Death Valley; not yet identified in salt pan; may be expected in carbonate zone of Cottonball Basin.

Dolomite

CaMg(CO₃)2

identified only as a detrital mineral; may be expected in carbonate zone.

Northupite

and/or

Tychite

Na₃MgCl(CO₃)

Na₆Mg₂(SO₄)·(CO₃)₄

An isotropic mineral, having index of refraction in the range of Northupite and Tychite, has been observed in saline facies of sulfate zone in Cottonball Basin.

Burkeite

Na₆(CO₃)(SO₄)₂

Sulfate zone in Cottonball Basin.

Thenardite

Na₂S0₄

Common in all zones in Cottonball Basin and in sulfate marshes in Middle and Badwater basins.

Mirabilite

Na₂S0₄·10H₂O

Occurs on floodplains in Cottonball Basin immediately following winter storms.

Glauberite

Na₂Ca(SO₄)₂

Common on floodplains except in central part of Badwater Basin; sulfate zone in Cottonball Basin.

Anhydrite

CaSO₄

As layer capping massive gypsum I mile north of Badwater. Possibly also as dry-period efflorescence on floodplains.

Bassanite

2CaSO₄·H₂O

As layer capping massive gypsum along west side of Badwater Basin and as dry-period efflorescence in floodplains.

Gypsum

CaS0₄·2H₂O

In sulfate caliche, layer in carbonate zone, particularly in Middle and Badwater basins, in sulfate marshes and as massive deposits in sulfate zone.

Hexahydrite

MgS0₄·6H₂O

Not yet identified but might he expected as dehydration product of epsomite in chloride zone on floodplains.

Epsomite

MgS0₄·7H₂O

Not yet identified; probably will he found as efflorescence on floodplains following storms or floods would dehydrate to hexahydrite during dry periods.

Bloedite

Na₂Mg(SO₄)₂·4H₂O

Questionably present in efflorescence on floodplain in chloride zone.

Polyhalite

K₂Ca2Mg(SO₄)₄·2H₂O

Questionably present on floodplain in chloride zone.

Barite

BaS0₄

Not yet identified but probably will be found in carbonate zone and as clastic grains in sediments underlying salt pan.

Celestite

SrSO₄

Found with massive gypsum.

Schairerite

Na₃(SO₄)(F,Cl)

Not yet identified, might he expected in Cottonball Basin or east side of Middle Basin.

Sulfohalite

Na₆ClF(SO₄)₂

Not yet identified, might he expected in Cottonball Basin or east side of Middle Basin.

Kernite

Na₂B₄O₇·5H₂O

Possibly present in Middle Basin in surface layer of layered sulfate and chloride salts.

Tincalconite

Na₂B₄O₇·10H₂O

Probably occurs as dehydration product of borax.

Borax

Na₂Mg(SO₄)₂·4H₂O

Floodplains and marshes in Cottonball Basin.

Inyoite

Ca₂B₆O₁₁·13H₂O

Questionably present (X-ray determination but unsatisfactory) in floodplain in Badwater Basin.

Meyerhofferite

Ca₂B₆O₁₁·7H₂O

Found in all zones in Badwater Basin and in rough silty rock salt in Cottonball Basin

Colemanite

Ca₂B₆O₁₁·5H₂O

Questionably present (X-ray determination but unsatisfactory) in floodplain in Badwater Basin.

Ulexite

NaCaB₅O₉·8H₂O

Common in floodplain in Cottonball Basin; known as "cottonball"

Proberite

NaCaB₅O₉·5H₂O

A fibrous borate with index of refraction higher than ulexite occurs on dry areas in Cottonball Basin following hot dry spells and in surface layer of smooth silty rock salt.

Soda niter

NaNO₃

Weak, but positive chemical tests obtained locally.