Wikipedia
Tequesquite or tequexquite (from Nahuatl tequixquitl) is a natural mineral salt containing compounds of sodium chlorate, sodium carbonate, and sodium sulphate, used in Mexico since pre-Hispanic times mainly as a food seasoning. It is found naturally in central Mexico particularly in previously lacustrine environments where the mineral salt forms a sedimentary crust.
Chemically it is an alkaline rock composed of various minerals, which changes its ratio according to where it is obtained. It consists mainly of sodium bicarbonate and common salt (sodium chloride), but also contains potassium carbonate, sodium sulfate and clay. Its appearance is similar to that of common table salt in coarseness, but with a more greyish color.
It is classified into four types: mousse, confitillo, husk and dust. The first two, which are the best, are obtained from the recession of water, and the latter two as natural efflorescence. The latter contain more dirt, so the other two are preferred.
In industry it is also used with fats - saponified to make soap and prepare canvases.
Some locations in Mexico where it is mined are Lake Texcoco, Tequixquiac and Tequexquinahuac in the state of Mexico, Laguna Tequesquitengo in the state of Morelos, Nopalucan and Tequexquitla, in the state of Tlaxcala , Tequisquiapan, in the state of Querétaro, Tequesquite, in the state of Jalisco, Totolcingo lagoon in the state of Puebla and La Salada, in the state of Zacatecas.
Sometimes it is confused with nitro tequesquite salt, but its chemical composition is completely different.