Quality grade classification of vermiculite
Grade four: the micro hydration of vermiculite, have similar appearance and mica, with without hydration of mica flakes peeling easy split, color is dark green or nearly black, a shiny glass, vermiculite after calcining the volume expansion of 3 times.
Three grade: vermiculite leaves smaller, thin pieces of some flexibility, surface uneven. The color is dark brown, dark green, somewhat glassy. After calcination, the volume of vermiculite expanded by 3~5 times.
Grade 1: vermiculite has large blades that can not be split into thin sheets. The color is brass, bronze or light green, pearl or fat luster, calcined into golden yellow, vermiculite volume expansion more than 8 times.Two grade: vermiculite leaves larger, not easy to split, peeled into a full sheet. The color is dark brown, brass and green, pearl luster or glass. After calcination, the volume of vermiculite expanded by 6 - 8 times.
