21. Marie Curie used pitchblende ore from J�chymov to isolate the element radium, a decay product of uranium. 22. Curie's systematic studies included two uranium minerals, pitchblende and torbernite ( also known as chalcolite ). 23. Her electrometer showed that pitchblende was four times as active as uranium itself, and chalcolite twice as active. 24. From a ton of pitchblende , one-tenth of a gram of radium chloride was separated in 1902. 25. This element was the first one discovered by the Curies while they were investigating the cause of pitchblende radioactivity. 26. They first separated out polonium from pitchblende in July 1898, and five months later, also isolated radium. 27. He was a student of Charles Friedel, was a close friend of pitchblende that the Curies had initiated. 28. While snooping around, Steve discovers the area is rich with pitchblende , an ore of uranium and radium. 29. Veins of this type contain dolomite, calcite, pitchblende , minor sulphides and selenides ( especially clausthalite ). 30. The only larger source for radium-containing pitchblende was the Institute for Radium Research in Vienna was opened.
