Description: You are buying one piece of opalized shell fossil from Lightning Ridge Specimens picked out randomly from the pile, please see picture above with ruler. Era: Cretaceous period 145 to 66 million years ago. Country / Location of origin: Australia, Lightning Ridge. 100% genuine or full refund. ~~~~~ Background Information on Opalised Fossils PRECIOUS RELICS FROM THE AGE OF DINOSAURS 100-million-year-old fossils, from the Early Cretaceous period! It was a time when dinosaurs and other ancient creatures lived, and when ancient reptiles swam in a shallow sea covering much of inland Australia. These are no ordinary fossils because these incredible relics are made of solid opal. They are Australian treasures, of global scientific interest, and among the most beautiful and valuable fossils in the world. How do opalised fossils form? Opal forms in cavities within rocks. If the cavity is there because part of a living thing – for example a bone, shell or pinecone – was buried in the sand or clay before it turned to stone, then the opal can form a fossil replica of the object that was buried. A fossil is simply “the remains or traces of an ancient animal or plant preserved in rock”. Opalised fossils form in ways similar to other fossils, except that here they are preserved in silica. Elsewhere, fossils are preserved in minerals such as agate, pyrite or limestone. The sediments that buried plant and animal remains in the opal fields were rich in silica from ancient volcanoes, so here we have fossils preserved as silica in the form of opal. Opalisation of plants and animal remains happens in two ways, and at Lightning Ridge, a combination of the following two processes is seen in many specimens.Internal details not preserved (‘jelly mould’ fossils). Opal starts as silica dissolved in water. When the silica solution fills an empty cavity left by a shell or bone that has rotted away – like jelly poured in a mould – it may harden to form an opalised cast of the original object. In these fossils, outside features can be beautifully preserved, but the internal structures are not recorded. Internal details preserved. If the silica seeps into the organic material before it decomposes, then the organic molecules can be replaced by silica. This preserves very fine details of structures inside the bone or plant. When the silica is transparent, this internal anatomy is visible from the outside: the fossil is ‘see through’.Opalised Fossils of Lightning Ridge What is important about Lightning Ridge’s opalised fossils?They can be incredibly beautiful! They are providing new and fascinating information about Australia's ancient heritage and the evolution of plants, animals and environments on the Australian continent. Of all the Australian opal fields, Lightning Ridge and some boulder opal fields are the only places that have opalised fossils of land-living and freshwater plants and animals. The other Australian opal fields have fossils of saltwater or marine organisms, which provide other important information about Australia's past and the ancient Eromanga Sea. Australia is the only place on earth that produces opalised bones of land-living animals including dinosaurs – and most of these are from Lightning Ridge. Lightning Ridge is the only significant dinosaur site in New South Wales. Opalised bones from fields like Coober Pedy, Andamooka and White Cliffs are from plesiosaurs, ichthyosaurs and pliosaurs, which are marine reptiles, not dinosaurs. Fossils are preserved here in silica in the form of opal. Some of them are see-through, including the only transparent fossils of large animal bones in the world. The Lightning Ridge fossils are of plants and animals that lived close to the South Pole, in global greenhouse conditions, in habitats unknown anywhere today. They are a window onto Australia’s past - important for scientists who study the evolution of Australian plants, or dinosaurs, or mammals, or climate change, geology and many other aspects of earth history. Fossil formation is closely linked to opal formation. Study of opalised fossils could provide important new information on opal formation, and help with opal exploration and prospecting. Reference: australianopalcentre.com
Price: 30 AUD
Location: Sydney
End Time: 2024-01-03T14:43:12.000Z
Shipping Cost: 20.57 AUD
Product Images
Item Specifics
Returns Accepted: ReturnsNotAccepted
Gemstone Type: Black Opal
Colour: Multi-Colour
