Well, the mass of Mars is 6.4×1023 kilograms, so if a 25 kg chunk of it is worth $5.3 million, that means the whole planet Mars is worth like 2.56×1022 x $5.3 × 106 = $1.36×1029 if I did my math right.
So that means all of Mars is worth 136 octillion dollars! 🙂