verre (2) Minerals (2) Glass (2) couche limite (1) zonage (1) puits (1) volcanisme (1) vallée (1) itinéraire (1) phosphore (1) minéral (1) fusion (1) infiltration (1) histoire (1) champ (1) évolution (1) enrichissement (1) Afrique (1) point (1) The Valley (1) History (1) Microscopy (1) Zoning (1) Volcanism (1) Veins (1) Spinel (1) Silicate minerals (1) Seepage (1) Igneous rocks--Inclusions (1) Rocks (1)