Click on a letter above to view the list of gems.    

Trona
Current inventory:  0 gems
 

  
Trona is named from a Swedish term derived from the Arabic word "natrum", meaning native salt.

Discovered in 1773;   IMA status: Valid (pre-IMA; Grandfathered).

Chemistry

Chemical Formula:

Na₃(CO₃)(HCO₃) • 2H₂O

Hydrated Sodium Bicarbonate Carbonate

Molecular Weight:

226.03 gm

Composition:  

Classification

Mineral Classification:

Carbonates

Strunz 8th Ed. ID:

5/D.02-30

Nickel-Strunz 10th Ed. ID:

5.CB.15

5 : CARBONATES (NITRATES)
C : Carbonates without additional anions, with H₂O
B : With large cations (alkali and alkali-earth carbonates)

Related to:

Thermonatrite - Chalconatronite Series

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Crystals are dominated by {001}, {100}, flattened on {001} and elongated on [010], with minor {201}, {301}, {211}, {211}, {411}, to 10 cm; may be fibrous or columnar massive, as rosettelike aggregates.

Twinning:

None

Physical Properties

Cleavage:

[100] Perfect, [111] Indistinct, [001] Indistinct

Fracture:

Irregular/Uneven, Sub-Conchoidal

Tenacity:

Brittle

Moh's Hardness:

2.5 - 3.0

Density:

2.11 - 2.17 (g/cm³)

Luminescence:

None or may fluoresce under SW UV

Radioactivity:

Not Radioactive

Other:

Soluble in water. Effervesces in acids.

Optical Properties

Color:

Colorless, Grayish White, Grayish, White, Yellowish White, Yellowish

Transparency:

Translucent

Luster:

Vitreous, Pearly

Refractive Index:

1.412 - 1.540  Biaxial ( - )

Birefringence:

0.1280

Dispersion:

Relatively Strong

Pleochroism:

None

Occurances

Geological Setting:

Deposited from saline lakes and along river banks as efflorescences in arid climates; rarely from fumarolic action.

Common Associations:

Glauberite, Gypsum Halite, Mirabilite, Natron, Thénardite, Thermonatrite (alkali lakes); Bradleyite, Northupite, Pirssonite, Shortite (Green River Formation, Wyoming, USA)

Type Locality:

Wadi Natrun depression, Western Desert, Egypt

Year Discovered:

1773

View mineral photos:

Trona Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Trona is a common carbonate mineral that forms as efflorescent crusts on the walls of caves and mines or in soils in arid regions. It is very rarely available as a faceted gem and is mainly an oddity for collectors. Trona is one of several sodium carbonate minerals that form in non-marine evaporite deposits. Other sodium carbonates include Gaylussite, Nahcolite, Natron, Northupite, Pirssonite and Thermonatrite. Of these, Trona is probably the most common and well known of these. All of them are very similar and difficult to tell apart except by the differences of good crystal forms when available or by optical X-ray techniques. All are subject to dehydration and/or hydration to varying degrees and should be stored in a sealed container.

Trona is widespread in arid regions although facet grade crystals are fairly rare. Historically important deposits in the lower Nile delta, near Memphis, Egypt, and elsewhere in the Sahara Desert, Africa. Large crystals at Lake Magadi, Kenya. Around Lake Chad, Chad. At Lake Katwe, western Uganda. From Lake Nyassa, Tanzania. At the Otjiwalundo salt pan, about 400 km west-northwest of Otavi, Namibia. At Lagunillas, about 80 km southeast of Merida, Venezuela. In the Beypazari deposit, west of Ankara, Turkey, estimated at over 200 million tons. On Vesuvius, and at Campi Flegrei, near Naples, Campania, Italy. In the USA, in California, at Searles Lake, San Bernardino County, Borax Lake, Lake County, and Owens Lake, Inyo County; extensive deposits, aggregating over 100 billion tons, occur in the Green River Formation, Wyoming, Colorado, and Utah; in Nevada, from Little Soda Lake, Churchill County, and elsewhere.
 

  
Trona gems for sale:

We have not photographed our Trona gems. Please check back soon.