Most potassium occurs in the Earth's crust as minerals, such as feldspars and clays. Potassium is leached from these by weathering, which explains why there is quite a lot of this element in the sea (0.75 g/liter). Minerals mined for their potassium are pinkish and sylvite, carnallite and alunite.
oppression - the act of subjugating by cruelty; the tyrant's oppression of the people. 2. oppression - the state of being kept down by unjust use of force or authority: after years of oppression they finally revolted. subjection, subjugation - forced submission to control by others. yoke - an oppressive power; under the yoke of a tyrant; they threw off the yoke of domination.
op-ed(Adjective) Of or being a newspaper page, usually opposite the editorial page, that features signed articles expressing personal viewpoints. op-ed(Adjective) Of an article, written in a style suitable for publication as an op-ed.