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
Common minke whale dwarf form in the Southern Hemisphere. This species is known in the fossil record from the Pliocene epoch to the Quaternary period (age range: 3.6 million years ago to present day). The origins of the species' common name are obscure. One of the first references to the name came in Henrik Johan Bull's account of his 1893–95 voyage to the Antarctic, when he mentioned catching a small whale "called in the Arctic language a Mencke whale, after a German who accompanied Mr. Foyn on some of his voyages." According to the British writer John Guille Millais ("The mammals of Great