THE MINERAL TRONA

  • Chemistry: Na3(HCO3)(CO3) - 2H2O , Hydrated Sodium Bicarbonate Carbonate.
  • Class: Carbonates
  • Uses: Only as mineral specimens.
  • Specimens

Trona is the type mineral so-to-speak for several sodium carbonates that form in non-marine evaporite deposits. Other sodium carbonates include gaylussite, natron, pirssonite, northupite, nahcolite and thermonatrite. Trona is probably the most common and well known of these minerals. They are all difficult to tell apart from each other except when good crystal form is present or when optical or X-ray techniques can be used. All are subject to dehydration and/or hydration to one degree or another and should be stored in sealed containers for this reason. All may form as efflorescent crusts on the walls of caves and mines or in soils in arid regions. Trona gets its name from a discarded Arabic word for native salt, "tron", which is derived from the word "natrun".

PHYSICAL CHARACTERISTICS:

  • Color is gray, colorless, white, pale brown or yellowish.
  • Luster is vitreous.
  • Transparency: Crystals are transparent to translucent.
  • Crystal System is monoclinic; 2/m.
  • Crystal Habits include prismatic to blocky crystals, but usually massive, fibrous or columnar.
  • Cleavage is perfect in one direction and poor in two others.
  • Fracture is subconchoidal to uneven.
  • Hardness is 2.5 - 3.
  • Specific Gravity is 2.1 (well below average)
  • Streak is white.
  • Other Characteristics: Has an alkaline taste.
  • Associated Minerals include hanksite, gaylussite, halite, pirssonite, northupite, nahcolite, borax and calcite.
  • Notable Occurrences include Searles Lake, San Bernardino County; Borax Lake, Lake County; Owens Lake, Inyo County and Mono Lake, Mono County, California and Green River, Wyoming, USA; Iran; Tibet; Mont Saint-Hilaire, Quebec, Canada and Mongolia.
  • Best Field Indicators: environment of formation, color, cleavage, density, crystal habit, taste and locality.
TRONA specimens:
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TRONA specimen tro-1
$ 48.00
Dims: 1.8 x 0.4 x 0.3" (4.6 x 1.0 x 0.7 cm)
Wt: 3 g
Searles Lake, Trona, San Bernardino County, California, U.S.A.
A parallel association of nearly complete Trona crystals makes up this small hand specimen. The crystals are in good condition, showing little damage, and have good monoclinic, bladed form. All are colorless and though they contain some dull gray-white inclusions, are transparent and moderately clear. There is no host rock present.
no photo
tro-1 ($ 48.00)
Searles Lake, Trona, San Bernardino County, California, U.S.A.
TRONA specimen tro-2
$ 68.00
Dims:3.6x2.7x2.2" (9.1x6.9x5.6 cm)
Wt: 5.8oz. (164g)
Owens Lake, Inyo cty., California
Delicate sprays of honey colored trona crystals grow up from the evaporite matrix rock of this specimen. These crystals of trona reach 1.5" (3.8cm) in length, and are extremely translucent. There is some damage to the edges of this specimen, where it was broken away from the host. All in all, this is a most aesthetic specimen.
no photo
tro-2 ($ 68.00)
Owens Lake, Inyo cty., California
TRONA specimen tro-3
$ 90.00
Dims:3.3x3.0x2.4" (8.4x7.6x6.1 cm)
Wt: 8.0oz. (228g)
Owens Lake, Inyo cty., California
The evaporite matrix of this specimen is host to excellent crystals of trona to 1.2" (3.0cm) in length. These crystals are a pale honey color, and are extremely translucent (nearly transparent in places). This is a beautiful display specimen. The only damage to this specimen is very minor damage at the edges, where it was pried from the host rock.
no photo
tro-3 ($ 90.00)
Owens Lake, Inyo cty., California
TRONA specimen tro-4
$ 50.00
Dims:2.4x2.2x2.1" (6.1x5.6x5.3 cm)
Wt: 3.1oz. (88g)
Owens Lake, Inyo cty., California
The evaporite matrix of this specimen is host to a cluster of trona crystals to 1.4" (3.6cm) in length. These crystals are in fine shape, with excellent terminations. They are very translucent. The only damage to this specimen is at the edges, where it was broken away from the host rock.
no photo
tro-4 ($ 50.00)
Owens Lake, Inyo cty., California

 


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