Did a Piece of "Quark Matter" Go Right Through the Earth? Source: http://www.smu.edu/newsinfo/releases/01342.html

... The so-called strange quark matter is so dense that a piece the size of a human cell would weigh a ton. ... This form of matter -- known as "strange quark matter" -- is so dense that a ton-sized nugget would be about the size of a red blood cell. ...

Here's a news item that will give you pause for thought !