Spotted Lake is visible from the road, 8.8 kms (5.5 miles) west of Osoyoos on Hwy. 3 ….a rare and unique natural phenomenon covering 15.2 hectares (38 acres). It contains one of the worlds highest concentrations of minerals: magnesium sulphate (Epsom salts), calcium and sodium sulphates, plus eight other minerals and traces of four more, including silver and titanium.
The therapeutic value of Spotted Lake has always proved interesting, however other uses were found for the minerals. During WWI, Chinese labourers were employed skimming the salts from the surface of the lake. The product was then shipped to Eastern American munitions factories.
Yield is said to have reached a ton per day. In the hot sun of summer, the water of Spotted Lake evaporates and crystallizes the minerals, forming many white-rimmed circles: shallow pools that reflect the mineral content of the water in shades of blues and greens.
Source: http://bored-bored.com/amazing/kliluk-the-spotted-lake/