It is not missing if you have anything other than a text only screen, it is a harmless to leave it like that, your system has found it but the "details" windows does not find it.
You can verify it by typing into a terminal:
lspci | less
the second entry will be your graphic card.
If you want to have it identified you can install
sudo apt-get install mesa-utils
mesa-utils will also give you some diagnostic programs to check that your 3D render is working properly such as:
glxdemo, glxgears, glxheads, glxinfo