An active vocabulary is made up of the words readily used and clearly understood by an individual when speaking and writing. Contrast with passive vocabulary. Martin Manser notes that an active vocabulary consists of the words that [people] use frequently and confidently. If someone asks them to make up a sentence containing such and such a wordâand they can do itâthen that word is part of their active vocabulary..
Roofing slate is a dense, durable, naturally occurring material that is essentially nonabsorbent. Two properties of slate are cleavage and fracture. It has natural cleavage, which permits it to be easily split in one direction.Fracture, usually occurring at right angles to the cleavage, is called the grain. Roofing slate commonly is split so the length of the slate runs in the direction of the grain.The surface texture of slate after being split for commercial use derives from the characteristics of the rock from which it was quarried.oofing slate is a dense, durable, naturally occurring material that is essentially nonabsorbent. Two properties of slate are cleavage and fracture. It has natural cleavage, which permits it to be easily split in one direction.
Slate can also contain abundant quartz and small amounts of feldspar, calcite, pyrite, hematite and other minerals. Most slates are gray in color and range in a continuum of shades from light to dark gray. Slate also occurs in shades of green, red, black, purple and brown.he color of slate is often determined by the amount and type of iron and organic material that are present in the rock. The tectonic environment for producing slate is usually a former sedimentary basin that becomes involved in a convergent plate boundary.