[填空题]
vA piece of material, suspected of bein+rzh+x4rneta0e9h pl4g ee* - g pawa. iiz; nmajx)yo8d7( 27pa stolen diamond $(n=2.42)$ is submerged in oil of refractive index 1.43 and illuminated by unpolarized light. It is found that the reflected light is completely polarized at an angle of 59$^{\circ}\,$. Is it diamond?
