Mercury, Atomic Mass : 200.59 u +/- 0.02 u

We are offering mercury.
Elemental mercury is a neurotoxin that causes nerve damage, hair loss and eventually death if you are exposed to enough of it. It is not absorbed through the skin or digestion, but only through inhaling it. It naturally evaporates so you must be careful not to be exposed to the fumes. It takes about three to six months for the mercury to work it's way out of your body, so it's easy to have it build up by being exposed to small amounts for long periods. The stuff splashes into microscopic droplets and is nearly impossible to clean up, so it has a well deserved reputation as being dangerous to handle. However, if you take precautions, make sure anything it touches is disposed of as hazardous waste and plan ahead you can avoid turning your living room into an EPA superfund site. It's not the safest chemical, but it's not deadly as instantly deadly as many are lead to believe.