| http://www.w3.org/ns/prov#value | - ater in a clay mineral matrix and as water of hydration (often in magnesium salts, 5% to 15%), 2% to 5% carbon in the form of graphite, hydrocarbons and organic compounds, several percent sulfur in elemental, iron sulfide and water soluble sulfate forms, some nitrogen and other volatiles, and 5% to 15% magnetite.
|
