Bromine and mercury are elements that appear dull and are in liquid form at room temperature.
Mercury is not dull. It is shiny. If you mean dull as in a dull blade then no because it is a liquid. It is not brittle in its state at room temperature since it is a liquid, but as a solid it is not that brittle it is actually pretty strong.
No, they get dull
A dull silvery grey metal
Calcium is a solid, soft dull grey metal at room temperature :)
a patter of behvior which has become hard to change
its appearance can change to a dull grey colour
When your strings begin to sound "dull".