  A quantum critical endpoint related to a metamagnetic transition causes
distinct signatures in the thermodynamic quantities of a compound. We argue
that, irrespective of the microscopic details of the considered material, the
diverging differential susceptibility combined with the Ising symmetry of the
endpoint give rise to a number of characteristic metamagnetic phenomena. In the
presence of a magnetoelastic coupling, one finds a correspondence of
susceptibility, magnetostriction and compressibility and, as a result, a
pronounced crystal softening, a diverging Grueneisen parameter, a sign change
of thermal expansion alpha(H), and a minimum in the specific heat coefficient
gamma(H). We illustrate these signatures and their relation on the metamagnetic
crossover at 8 T in the prototypical heavy-fermion system CeRu2Si2.
