A method for the separation of inactive Vitamin K dependent protein from active Vitamin K dependent protein in a method for the purification of a Vitamin K dependent protein comprising the steps of: (a) loading an anion exchange resin material (in the following also "the first anion exchange resin material") with the Vitamin K dependent protein in a loading buffer in the absence or low concentration of divalent cations, optionally followed by one to three wash steps; (b) eluting the Vitamin K dependent protein with an eluant comprising calcium and a counter-anion to form an eluate containing the Vitamin K dependent protein, wherein: - 1-3 mM calcium is comprised in the eluant - the eluant has a conductivity of 14 - 23 mS/cm (25°C), and - the pH of the eluant is between 7.0 and 9.0, wherein step (b) is selected from the following group: - the conductivity is between 18 and 20 mS/cm (25°C) at a pH of 7.0 -7.4 and 1 mM Ca ++, - the conductivity is between 18.5 and 21 mS/cm (25°C) at a pH of 7.4 - 7.6 and 1 mM Ca ++, - the conductivity is between 19 and 22.5 mS/cm (25°C) at a pH of 7.6 - 8.0 and 1 mM Ca ++, or - the conductivity is between 20 and 23 mS/cm (25°C) at a pH of 8.0 - 9.0 and 1 mM Ca ++, - the conductivity is between 15 and 17.0 mS/cm (25°C) at a pH of 7.0 - 7.4 and 2 mM Ca ++, - the conductivity is between 16 and 18 mS/cm (25°C) at a pH of 7.4 - 7.6 and 2 mM Ca ++, - the conductivity is between 19.5 and 22 mS/cm (25°C) at a pH of 8.0 - 9.0 and 2 mM Ca ++, - the conductivity is between 14.0 and 15 mS/cm (25°C) at a pH of 7.0 - 7.4 and 3 mM Ca ++, - the conductivity is between 15 and 15.5 mS/cm (25°C) at a pH of 7.4 - 7.6 and 3 mM Ca ++, - the conductivity is between 14 and 16.5 mS/cm (25°C) at a pH of 7.6 - 8.0 and 3 mM Ca ++, or - the conductivity is between 15 and 19 mS/cm (25°C) at a pH of 8.0 - 9.0 and 3 mM Ca ++. (a) loading an anion exchange resin material (in the following also "the first anion exchange resin material") with the Vitamin K dependent protein in a loading buffer in the absence or low concentration of divalent cations, optionally followed by one to three wash steps; (b) eluting the Vitamin K dependent protein with an eluant comprising calcium and a counter-anion to form an eluate containing the Vitamin K dependent protein, wherein: - 1-3 mM calcium is comprised in the eluant - the eluant has a conductivity of 14 - 23 mS/cm (25°C), and - the pH of the eluant is between 7.0 and 9.0, wherein step (b) is selected from the following group: - the conductivity is between 18 and 20 mS/cm (25°C) at a pH of 7.0 -7.4 and 1 mM Ca ++, - the conductivity is between 18.5 and 21 mS/cm (25°C) at a pH of 7.4 - 7.6 and 1 mM Ca ++, - the conductivity is between 19 and 22.5 mS/cm (25°C) at a pH of 7.6 - 8.0 and 1 mM Ca ++, or - the conductivity is between 20 and 23 mS/cm (25°C) at a pH of 8.0 - 9.0 and 1 mM Ca ++, - the conductivity is between 15 and 17.0 mS/cm (25°C) at a pH of 7.0 - 7.4 and 2 mM Ca ++, - the conductivity is between 16 and 18 mS/cm (25°C) at a pH of 7.4 - 7.6 and 2 mM Ca ++, - the conductivity is between 19.5 and 22 mS/cm (25°C) at a pH of 8.0 - 9.0 and 2 mM Ca ++, - the conductivity is between 14.0 and 15 mS/cm (25°C) at a pH of 7.0 - 7.4 and 3 mM Ca ++, - the conductivity is between 15 and 15.5 mS/cm (25°C) at a pH of 7.4 - 7.6 and 3 mM Ca ++, - the conductivity is between 14 and 16.5 mS/cm (25°C) at a pH of 7.6 - 8.0 and 3 mM Ca ++, or - the conductivity is between 15 and 19 mS/cm (25°C) at a pH of 8.0 - 9.0 and 3 mM Ca ++. - 1-3 mM calcium is comprised in the eluant - the eluant has a conductivity of 14 - 23 mS/cm (25°C), and - the pH of the eluant is between 7.0 and 9.0, wherein step (b) is selected from the following group: - the conductivity is between 18 and 20 mS/cm (25°C) at a pH of 7.0 -7.4 and 1 mM Ca ++, - the conductivity is between 18.5 and 21 mS/cm (25°C) at a pH of 7.4 - 7.6 and 1 mM Ca ++, - the conductivity is between 19 and 22.5 mS/cm (25°C) at a pH of 7.6 - 8.0 and 1 mM Ca ++, or - the conductivity is between 20 and 23 mS/cm (25°C) at a pH of 8.0 - 9.0 and 1 mM Ca ++, - the conductivity is between 18 and 20 mS/cm (25°C) at a pH of 7.0 -7.4 and 1 mM Ca ++, - the conductivity is between 18.5 and 21 mS/cm (25°C) at a pH of 7.4 - 7.6 and 1 mM Ca ++, - the conductivity is between 19 and 22.5 mS/cm (25°C) at a pH of 7.6 - 8.0 and 1 mM Ca ++, or - the conductivity is between 20 and 23 mS/cm (25°C) at a pH of 8.0 - 9.0 and 1 mM Ca ++, - the conductivity is between 15 and 17.0 mS/cm (25°C) at a pH of 7.0 - 7.4 and 2 mM Ca ++, - the conductivity is between 16 and 18 mS/cm (25°C) at a pH of 7.4 - 7.6 and 2 mM Ca ++, - the conductivity is between 19.5 and 22 mS/cm (25°C) at a pH of 8.0 - 9.0 and 2 mM Ca ++, - the conductivity is between 14.0 and 15 mS/cm (25°C) at a pH of 7.0 - 7.4 and 3 mM Ca ++, - the conductivity is between 15 and 15.5 mS/cm (25°C) at a pH of 7.4 - 7.6 and 3 mM Ca ++, - the conductivity is between 14 and 16.5 mS/cm (25°C) at a pH of 7.6 - 8.0 and 3 mM Ca ++, or - the conductivity is between 15 and 19 mS/cm (25°C) at a pH of 8.0 - 9.0 and 3 mM Ca ++.