Common bleak extracted from the scales of the common bleak, so-called "Essence Orientale" or "pearl essence", (used in making artificial pearls) which is crystalline guanine. Common bleak The common bleak ("Alburnus alburnus") is a small freshwater coarse fish of the cyprinid family. The body of the bleak is elongated and flat. The head is pointed and the relatively small mouth is turned upwards. The anal fin is long and has 18 to 23 fin rays. The lateral line is complete. The bleak has a shiny silvery colour; and the fins are pointed and colourless. The maximum length is approximately 25 cm. In
Fin whale Fin whale The fin whale ("Balaenoptera physalus"), also known as finback whale or common rorqual and formerly known as herring whale or razorback whale, is a marine mammal belonging to the parvorder of baleen whales. It is the second-largest species on Earth after the blue whale. The largest reportedly grow to long with a maximum confirmed length of , a maximum recorded weight of nearly , and a maximum estimated weight of around . American naturalist Roy Chapman Andrews called the fin whale "the greyhound of the sea ... for its beautiful, slender body is built like a racing yacht