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Trona
Chemical Formula	Na3(CO3)(HCO3)?2H2O
Species	Carbonates
Crystal System	Monoclinic
Mohs Scale	2
Specific Gravity	2.11-2.17
Color	Colorless or white, also grey to yellowish grey
Streak	White
Luster	Vitreous
Refractive Index	n = 1.412 n = 1.492 n = 1.540
Diaphaneity	Translucent
Cleavage	PerfectOn perfect; on and in traces.
Fracture	Irregular/Uneven, Sub-Conchoidal
Crystal Habit：Columnar, fibrous and massive.
Geological Setting：Saline lakes and their evaporites; efflorecences on soils in arid regions.

Trona (trisodium hydrogendicarbonate dihydrate); Na₃(CO₃)(HCO₃)?2H₂O is an evaporite mineral. It is mined as the primary source of sodium carbonate in the United States, where it has replaced the Solvay process used in most of the rest of the world for sodium carbonate production.

Etymology

The word "trona" comes to English by way of either Swedish (trona) or Spanish (trona), with both possible sources having the same meaning as in English. Both of these derive from the Arabic trōn which in turn derives from the Arabic natron, and Hebrew ???? (natruna), which comes from ancient Greek νιτρον (nitron), derived ultimately from ancient Egyptian ntry (or nitry).

Natural deposits

Trona is found at Owens Lake and Searles Lake, California; the Green River Formation of Wyoming and Utah; the Makgadikgadi Pans in Botswana and in the Nile Valley in Egypt. The trona near Green River, Wyoming is the largest known deposit in the world and lies in layered evaporite deposits from 800 to 1,600 feet (240 to 490 m) below ground, where the trona was deposited in a lake during the Paleogene period. Trona has also been mined at Lake Magadi in the Kenyan Rift Valley for nearly 100 years, and occurs in 'salt' pans in the Etosha National Park in Namibia.^{[citation needed]}

Mining operations

• Magadi Soda Company
• Searles Valley Minerals Inc.
• Solvay
• Tata Chemicals
• FMC Corporation
• General Chemical
• OCI Chemical Corp.
• American Natural Soda Ash Company