Appearance
Grey cylindrical pills (no more than 1% pulverised)

Rhenium content
99.9 % minimum

Impurities as detected
Bi - 1 ppm maximum
Pb, Ag, Ca, Se, Te, Tl - 5 ppm maximum each
As, Na, Sn - 10 ppm maximum each
Si, Mn, S, Th - 20 ppm maximum each
Al - 30 ppm maximum
C, N, Cd, H, K - 50 ppm maximum each
Cu - 70 ppm maximum
Co, Cr, Fe, Ni, Mg - 100 ppm maximum each
P, B, Hf, Nb, Ta, Ti, V, Zr, Ga, In, Sb, Zn - 200 ppm maximum each
O, Mo, W - 500 ppm maximum each