. . . "High-purity silica placers undercover karstification cryptokarsts physical properties chemical properties quartz ore"@en . "Placers de silice ultra-pure karstification sous couverture cryptokarsts caract\u00E9ristiques physiques caract\u00E9ristiques chimiques minerai quartz"@fr . . "Fluviatile gravels"@en . "Laurent" . "High-purity silica placers"@en . "Quartz-Gisements"@fr . "Covered karst"@en . "Silice-Gisements"@fr . "Cryptokarstic corrosion"@en . <084553510> . "Silice-\u00E9lectrom\u00E9tallurgie"@fr . "Karst"@fr . "Laurent D\u00E9sindes" . "Silicium-\u00E9lectrom\u00E9tallurgie"@fr . . "Dordogne France"@en . "D\u00E9sindes" .