Alkali

Lithium, sodium, potassium, rubidium, caesium and francium are alkali metals.

Source: tatoeba (1555667)

Calcium is not an alkali metal.

Source: tatoeba (4462487)

There are swift-flowing rivers which dash through jagged cañons; and there are enormous plains, which in winter are white with snow, and in summer are grey with saline alkali dust.

Source: tatoeba (6310196)

It has been said there is nothing appertaining to life upon the broad plain. That is hardly true. Looking down from the Sierra Blanco, one sees a pathway traced out across the desert, which winds away and is lost in the extreme distance. It is rutted with wheels and trodden down by the feet of many adventurers. Here and there there are scattered white objects which glisten in the sun, and stand out against the dull deposit of alkali. Approach and examine them! They are bones: some large and coarse, others smaller and more delicate. The former have belonged to oxen, and the latter to men. For fifteen hundred miles one may trace this ghastly caravan route by these scattered remains of those who had fallen by the wayside.

Source: tatoeba (6310209)