Mayan temple at night. This is El Castillo (the castle), part of the Mayan city of Chichen Itza in Yucatan, Mexico. This structure stands at 22 metres high. The construction of this pyramid was planned so that during the spring equinox (around 21 March), the setting sun casts a shadow of a snake writhing down the pyramid's steps. The Maya were Native American people, originating in Yucatan around 2600 BC. They developed astronomy, calendrical systems and hieroglyphic writing from the ideas of earlier civilizations. Mayan civilization went into decline in AD 900 and came to a close in AD 1200.
© TONY CRADDOCK/SCIENCE PHOTO LIBRARY
Native copper, macrophotograph
Native copper. Native copper is copper found naturally in a pure (chemically uncombined) state. Native copper deposits are now almost depleted and most mining concentrates on copper-containing minerals. Copper is a soft, dense, ductile and malleable metal, that forms the base for alloys such as bronze and brass. It is also an excellent conductor and is used for electrical wiring. This sample was found in Michigan, USA. Object size approx. 10mm.
© PASIEKA/SCIENCE PHOTO LIBRARY
Gold, Carnon Stream Works, Perranarworthal, Cornwall, England
Gold is a native element and precious metal which has been prized by mankind for thousands of years for its beauty, malleability and resistance to corrosion. This gold nugget is the largest known to have been found in Cornwall and weighs 1 oz t, 18 dwt. 6 grs. It was found in January 1808 in the Carnon Valley tin-stream works and bought by collector Philip Rashleigh in March of the same year. Rashleigh wrote in his Manuscript (112 Au): 'Native Gold found in Carnon Stream work in Cornwall weighs - 1 oz. 18 pw. 6 gr. Troy this piece has had all the extra matter picked out except a mite in one place the marks of many others remain. The smoothness of the piece shews the great time it has been washed by the water where it was exposed and the hollow parts more rough gives a proof of its not being manufactured'. In the ownership of Mr Wills, a silversmith from Truro, the find was reported in the Royal Cornwall Gazette on 6th February 1808 'this is unquestionably the largest and most beautiful specimen ever found in Cornwall, or probably in any other country'. The paper reported in March 1808 that Rashleigh purchased the specimen from Mr Wills. Mineral analysis undertaken in 2018 indicates that the gold content in the nugget is in the high 90s while other gold nuggets from the Carnon Stream Works, which were analysed, are around the 70s. As a result, it has been suggested that this gold nugget may have been refined and worked into a forgery by the silversmith who sold it to Rashleigh. Rashleigh Collection.
© RIC, photographer A.G. Tindle