Carbonates & Nitrates

Dolomite

• CaMg(CO3)2

• PEARL SPAR

• Does not stain using Lemberg’s test

• Saccharoidal Texture

• Glide Twin Lamellae and Simple Twinning

• SG 2.86

Ankerite

• Ca(MgFe)(CO3)2 (when Mg<Fe)

• BROWN SPAR, RHOMB SPAR, BITTER SPAR

• Sg 3.10

Calcite

• CaCO3

• ICELAND SPAR

• Hardness 3

• Sg 2.71

• Extreme MAXIMUM Birefringence

• PINK stain through Lemberg’s test using aluminum chloride or ferric chloride and logwood.

Alstonite

• BROMLITE

• (Ba,Ca)CO3

Barytocalcite

• BaCa(CO3)

• Monoclinic

• effervesces with hydrochloric acid

Thermonatrite

• Na2CO3-H2O

• Orthorhombic

• platy, acicular, efflorescent

Natron

• Na2CO3-10H2O

• Monoclinic

• Alkaline taste

• Very soluble in water

• Effervesces with acid

Trona

• URAO

• Na3H(CO3)2-H2O

• Monoclinic

• Alkaline taste

• Soluble in water

Gaylussite

• Na2Ca(CO3)2-5H2O

• Monoclinic

• Flattened wedge shaped like crystals

• Cleavage primatic {110} perfect

• occurs with other evaporites in muds and other sediments

Zaratite

• EMERALD NICKLE

• Ni₃(CO₃)(OH₂)-4H₂O

• Cubic

• Color emerald green

• Streak is pale green

• Green and isotopic in thin section with low relief

• Dissolves with effervescence when heated in dilute hydrochloric acid

Hydrozincite

• Zn5(CO3)2(OH)6

• Monoclinic

• results from the alteration of sphalerite

Malachite

• CuCO3(OH)2

• 57.3% Copper

• Monoclinic

• Color bright green or shades of green

• Dissolves and effervesces with acid

• Valuable ore of copper

Phosgenite

• CHROMFORDITE

• HORN LEAD

• Pb₂(CO₃)Cl

• Tetragonal

Bismutite

• BASOBISUTITE

• Bi2O2(CO3)

• Results from the alterations of native bismuth and bismuthinite

Azurite

• CHESSYLITE, blue carbonate of copper

• Cu3(CO3)2(OH)2

• 55.1% copper

• Monoclinic

• Deep azure blue

• Streak blue

• Blue in thin section

Leadhillite

• PbSO₄.2PbCO₃.Pb(OH) or Pb₄SO₄(CO₃)₂(OH)

• Monoclinic

• Tabular

• alteration probucts of galena or cerrusite

Magnesite

• MgCO3

• trigonal

Siderite

• FeCO3

• CHALYBITE

• Trigonal

Rhodocrosite

• MnCO3

• DIAGOLITE

• Trigonal

• alters to Pyrolusite (MnO2) or Pyrolusite [MnO(OH)]

Smithsonite

• ZnCO3

• Trigonal

• Important ore of zinc

• alters to hemimorphite or limonite

Witherite

• BaCO3

• Orthorhombic

• aragonite group

Strontianite

• SrCO3

• Orthorhombic

• alters to celestite

• aragonite group

Cerussite

• PbCO3

• CERUSE, WHITE LEAD ORE

• Orthorhombic

• Very high to extremely high relief

• Alteration product of galena w/ anglesite representing intermediate stage

• aragonite group

Aragonite

• CaCO3

• FLOSS FERRI

• Orthorhombic

• Hardness 4

• Sg 2.95

• Extinction straight , length fast

• Lamellar twins

• turns pink through Niegen’s test - stained w/ cobalt nitrate

• turns gray then black using leitmerier and figel’s test - using manganese sulfate

  • good for fine intergrowth

Soda Niter

• NITRATINE

• NITRATE OF SODA

• CHILE SALT PETER

• NaNO₃

• Trigonal

• Cooling taste

• Soluble in water

Niter

• SALTPETER

• NITRATE OF POTASH

• KNO3

• Orthorhombic

• Cyclic twins

• Taste saline and cooling