Concept:
Refractories are materials that can withstand high temperatures without softening or melting. Super refractories are the highest temperature class of refractories.
Step 1: Ordinary refractory materials are used at high temperatures.
Step 2: High refractory materials withstand still higher temperatures.
Step 3: Super refractory materials have very high fusion temperatures.
Step 4: A refractory material is called super refractory when its fusion temperature is above:
\[
2000^\circ C
\]
Therefore, the correct answer is:
\[
\boxed{2000^\circ C}
\]