The ability to levitate and detect height and orientation of diamagnetic objects suspended in paramagnetic solutions using an inhomogeneous magnetic field is described. By comparing the measured height and orientation of a sample material with the measured height and orientation of a reference material, quality control of objects can be carried out. The major advantages of this quality control technique are: i) it is a simple apparatus that does not require electric power (a set of permanent magnets and gravity are sufficient for the diamagnetic separation and collection system to work); ii) it is compatible with simple optical detection; iii) it is a cost-effective and simple method that can carry out quality control between sample and reference materials rapidly.