Exogangue

The exogangue is composed of diatom fragments with minor amounts of volcanic ash, very fine quartz and feldspar grains, sponge spicules, and organic matter.

The winnowing away of siliciclastic exogangue in nearshore locations is capable of converting a commercially low-grade deposit into a more uniform high-grade one.

The observation O.E.K’s phosphates under binocular magnifying glass, after mixing simples with water shows that: the phosphatic elements are primarily made up of pellets, osseous remains, tooth of squales and oolites; the exogangue is composed of quartz, calcite, dolomite, gypsum and clay; the endogangue is not very abundant about 3%.