A sample of pure water was spiked with 0.475 ng/mL silver ion. Ten replicate determinations of the spiked water sample gave 0.485 , 0.465 , 0.442 , 0.428 , 0.469 , 0.449 , 0.453 , 0.457 , 0.435 , and 0.420 ng/mL silver ion. Determine the mean percent recovery of the spike and the detection limit of the analytical method used for the silver ion determination.

Pegmatites are igneous rocks in which the individual minerals are very large. typically, the minerals are all light-colored quartz, feldspar and muscovite. if you were given a black and white photograph of a pegmatite in a quarry (where the rock has been blasted and broken), what physical properties could you use to identify those three minerals in this hypothetical photo? describe each mineral and the specific diagnostic properties. be specific.