![]() ![]() But it’s also very fragile, and you can easily break one by dropping it or throwing it against something hard. It’s super durable, great at repelling liquids and can be polished to a high shine. You can also write on a slate by using your finger. Writing on a slate is sometimes used for drawing or for writing messages. You can write on it with chalk or pens, and you can write on it by rubbing or scrubbing it with a damp cloth. Put simply, a slate is a writing surface where you can write or draw on it, but it can also be used to write on. Slate is considered to be between 2.5 to 4 on this scale in terms of hardness, which means that it is, on average, almost as hard as marble and limestone, but not as hard as granite or natural quartz. Among other things made from slate are blackboards, tabletops, and draining boards. One of its chiefs uses is as a roofing material for homes and buildings of all kinds. Slate occurs only where mountain-making pressure and earth changes have been acting upon the layers of old shale. The reason it is chiefly black is that the living matter in the original muds left carbon material. The most common colors of slate are dark grey and black, though it may also be red, green, or various shades of grey. And today we can split slate into wide, thin plates because it did stay in layers. Even after the pressure changed the shale to slate, the many separate layers of the deposits remained. The clay particles making up the slate were deposited by the lakhs and seas in layers. These were fattened and squeezed so hard that the shale became slate. The layers of shale, covered by beds of other rocks, wore folded up into wrinkles. This later hardened into the mud-rock that is called “shale”.ĭuring this period, the earth’s crust moved and shifted. Millions of years ago, fine-grained clay particles settled on the bottoms of lakes and inland seas and formed a soft mud. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |