Iâve come across a historical footnote on the English language and I thought everyone would get a kick out of it. Up until about 2 hundred years ago, there was a 27th letter in the English language. This letter is still in common use today and I would bet that you have used it recently. But this letter is no longer considered a letter; it is now regarded either an abbreviation or punctuation. Iâm talking about the (&) ampersand.
Gneiss is a medium to coarse-grained, irregularly banded rock with only poorly developed cleavage. The light and dark bands (gneissic banding) are alternations of felsic vs. mafic layers. Slate is a product of low grade metamorphism (not terribly great burial temperatures and pressures are required).
Round. Sand is defined by its size rather than what type of mineral it is. Particle size or grain size refers to the diameter of a grain of granular material. Technically, particles that fall between one-sixteenth of a millimeter to two millimeters in diameter are referred to as Sand.article size or grain size refers to the diameter of a grain of granular material. To determine a sand granule size, a sample is vibrated through a set of sieves of known mesh sizes. For sand the mesh size of the sieve can range from a No. 10 sieve which is 2 mm to a No. 200 sieve which is .075 mm mesh size.