Chalk It is formed in the sea by sub-microscopic plankton, which fall to the sea floor and are then consolidated and compressed during diagenesis into chalk rock. Most people first encounter the word "chalk" in school where it refers to blackboard chalk, which was originally made of mineral chalk, since it readily crumbles and leaves particles that stick loosely to rough surfaces, allowing it to make writing that can be readily erased. Blackboard chalk manufacture now may utilize mineral chalk, other mineral sources of calcium carbonate, or the mineral gypsum (calcium sulfate). While gypsum-based blackboard chalk is the lowest cost to
Pick-up sticks (Haida) Pick-up sticks (Haida) Haida pick-up sticks exist in two sorts. There were non-decorated thin playing sticks (not collected) and the other decorated, containing three sets of sticks. These were named after animals or birds only known by the owner or his family, according to Charles F. Newcombe. The decoration consists of rings and spiral markings for distinction. Most elaborated sets may contain a Haida art gallery of more than fifty drawings. Made of maple wood, they are decorated with pyro-engravings or carvings. Many pyro-engravings are inlaid with copper or abalone shell. The drawings are complex and an artistic challenge as