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.
Type HH, also known as Bombay blood, is named for where it was discovered. It is so rare that it is believed that less than 100 people in the world are known to have this blood type.That would mean that, in the event of an emergency, people who possess this particular group of blood would be placed in imminent danger.ype HH, also known as Bombay blood, is named for where it was discovered. It is so rare that it is believed that less than 100 people in the world are known to have this blood type.