A scale used to measure the relative hardness of a mineral by its resistance to scratching. From softest to hardest, the ten minerals of the Mohs scale are talc (measuring 1 on the scale), gypsum, calcite, fluorite, apatite, orthoclase, quartz, topaz, corundum, and diamond (measuring 10 on the scale).
Guinness World Records lists the Mona Lisa as having the highest insurance value for a painting in history. On permanent display at The Louvre museum in Paris, the Mona Lisa was assessed at US$100 million on December 14, 1962. Taking inflation into account, the 1962 value would be around US $780 million in 2014 dollars
Between 1937 and 1991, when he died aged 87, he published more than 40 books, which have sold half a billion copies between them – more even than J K Rowling’s Harry Potter books. He nearly burned his first book, And to think that I saw it on Mulberry Street, after it was turned down by 27 publishers.