A tetrahedron with identical isosceles or scalene faces.
Disphenoid
See also
Heronian Tetrahedron, Isosceles Tetrahedron, Snub DisphenoidExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Disphenoid." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Disphenoid.html