Most Total Time Spent in Space. Soviet cosmonaut Sergei Krikalev holds this record, with a little more than 803 days accrued over six spaceflights. That's more than two years and two months spent zipping around the Earth.
Natural citrines are rare. Most commercial citrine is heat-treated amethyst or smoky quartz. Because the color is now caused by finely distributed iron minerals (mostly hematite and goethite), heated amethyst is not a citrine in the strict sense.Quartz colored by inclusions of any kind is not called a citrine.atural citrines are rare. Most commercial citrine is heat-treated amethyst or smoky quartz. Because the color is now caused by finely distributed iron minerals (mostly hematite and goethite), heated amethyst is not a citrine in the strict sense. Quartz colored by inclusions of any kind is not called a citrine.
The penny is rare because it's one of only three known 1936-dated Canadian cents struck by the Royal Canadian Mint with a small but distinctive dot below the date to indicate it actually was made in 1937. rare Canadian penny billed as the king of Canadian coins was purchased for $402,500 US at a New York auction Sunday. The famed 1936 Canadian Dot Cent was the highlight of a group of coins billed as the single most substantial collection of Canadian coins ever offered at public auction.