Strontium:
Symbol: Sr
Atomic Number: 38
Atomic Weight: 87.62
From Strontian, Scotland; discovered 1790. A rare earth element which is a sort of evil alter ego of life-supporting calcium. Radioactive strontium 90 is present in atomic fallout. It is absorbed by bone tissue in place of calcium, and enough of it destroys marrow and can cause cancer. - Time-Life Science Series.