[mathattack]

Isn't everything on the earth this old? The dirt in our backyard has been around for 4.4 billion years too. Or is it that this crystal hasn't been changed in that long?

[s0rce]

It solidified from the melt 4.4 billion years ago and hasn't remelted since.

[Sharlin]

Or otherwise changed. Metamorphism doesn't involve melting.

[chongli]

When you put it that way, everything in the universe is the same age.

[mathattack]

That's where I was going. What do they mean by age?

Although one could argue that the speed things travel through the universe alters their age, but from when the Earth materialized, it shouldn't change much from particle to particle.

If you're arguing for "oldest living thing" I do get it.

[evilduck]

The dirt in your back yard hasn't been around for 4.4b years. Topsoil (decayed organic material and newly eroded rocks mostly) is usually pretty 'young' on geological timescales.

[lutorm]

Not in that form, but the vast majority of the matter certainly has been part of the Earth for that long.

By the same definition, I'm not 40 years old either, because practically no part of me is left since I was born.

[mathattack]

Right, but at least we can say you're a relatively old "living" creature where age is a more relevant number. (I'm getting up there in "relatively old" years too.)

[vacri]

We get new material thrown on us by space every day.

[jokoon]

breaking news: scientist claims to have found quarks which existed since the big bang.