Concept:
Whiteware bodies are commonly prepared using three main raw materials. These are called triaxial materials.
Step 1: The three main triaxial materials used in whiteware are:
\[
\text{Clay},\quad \text{Feldspar},\quad \text{Quartz}
\]
Step 2: Clay provides plasticity to the ceramic body and helps in shaping.
Step 3: Feldspar acts as a flux. It lowers the vitrification temperature and helps in forming a glassy phase during firing.
Step 4: Quartz acts as a filler and improves dimensional stability.
Step 5: Rutile is mainly titanium dioxide mineral:
\[
TiO_2
\]
It is not one of the three basic triaxial materials of whiteware.
Therefore, the material which is not a triaxial material in whiteware is:
\[
\boxed{\text{Rutile}}
\]