Resumen
Calcite e-twinning has been used for stress inversion purposes since the fifties. The commonlyused technique is the Etchecopar method (e.g. Laurent et al., 1981), based on testing of 500-1000randomly generated reduced stress tensors using a penalization function fL. A systematic search of allpossible reduced stress tensors with a new penalization function fR double checked with a spatial distributionplot is suggested.