A treatment method for modifying a reflected colour of a synthetic sapphire material surface with a wavelength range from 400 nm to 800 nm, said method comprising bombardment of the sapphire material surface by a gas ion beam so as to produce an ion-implanted layer in the sapphire material, wherein: - the gas ion beam comprises single- and multi-charged ions, and comprises 10% or more of multicharged ions, - an acceleration voltage is chosen in a range between 5kV and 100 kV, - a dose of implanted single- and multi-charged gas ions per unit of surface area of each ion beam is chosen in a range between 10 16 ions/cm 2 and 10 18 ions/cm 2; and - the ions of the gas ion beam are selected from ions of the elements from the list consisting of helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), boron, carbon, nitrogen, oxygen, fluorine, silicon (Si), phosphorus and sulphur, so as to obtain a modified reflected colour of the treated sapphire material surface compared to the untreated sapphire material surface, whereby the dominant wavelength, λ DT, of the reflected colour of the treated sapphire material surface is shifted from at least +50 nm or at least -50 nm from the dominant wavelength, λ DU, of the reflected colour of the untreated sapphire material surface, - the acceleration voltage and the dose of implanted single and multi-charged gas ions are chosen in a step prior to bombardment by a single- and multi-charged gas ion beam of the sapphire material to be treated, which consists in choosing one type of single- and multi-charged ions of the elements from the list consisting of helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), boron, carbon, nitrogen, oxygen, fluorine, silicon (Si), phosphorus and sulphur, performing a plurality of experiments with sapphire materials similar to the one to be treated using ions of the type chosen, and varying the implanted single- and multi-charged gas ion dose per unit of surface area and the acceleration voltage until determining desired implanted single- and multi-charged gas ion dose per unit of surface area ranges and acceleration voltage ranges so as to produce an ion implanted layer suitable for obtaining a modified reflected colour of the treated sapphire material surface compared to the untreated sapphire material surface, whereby the dominant wavelength, λ DT, of the reflected colour of the treated sapphire mateiral surface is shifted from at least +50 nm or at least -50 nm from the dominant wavelength, λ DU, of the reflected colour of the untreated sapphire material surface. - the gas ion beam comprises single- and multi-charged ions, and comprises 10% or more of multicharged ions, - an acceleration voltage is chosen in a range between 5kV and 100 kV, - a dose of implanted single- and multi-charged gas ions per unit of surface area of each ion beam is chosen in a range between 10 16 ions/cm 2 and 10 18 ions/cm 2; and - the ions of the gas ion beam are selected from ions of the elements from the list consisting of helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), boron, carbon, nitrogen, oxygen, fluorine, silicon (Si), phosphorus and sulphur, so as to obtain a modified reflected colour of the treated sapphire material surface compared to the untreated sapphire material surface, whereby the dominant wavelength, λ DT, of the reflected colour of the treated sapphire material surface is shifted from at least +50 nm or at least -50 nm from the dominant wavelength, λ DU, of the reflected colour of the untreated sapphire material surface, - the acceleration voltage and the dose of implanted single and multi-charged gas ions are chosen in a step prior to bombardment by a single- and multi-charged gas ion beam of the sapphire material to be treated, which consists in choosing one type of single- and multi-charged ions of the elements from the list consisting of helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), boron, carbon, nitrogen, oxygen, fluorine, silicon (Si), phosphorus and sulphur, performing a plurality of experiments with sapphire materials similar to the one to be treated using ions of the type chosen, and varying the implanted single- and multi-charged gas ion dose per unit of surface area and the acceleration voltage until determining desired implanted single- and multi-charged gas ion dose per unit of surface area ranges and acceleration voltage ranges so as to produce an ion implanted layer suitable for obtaining a modified reflected colour of the treated sapphire material surface compared to the untreated sapphire material surface, whereby the dominant wavelength, λ DT, of the reflected colour of the treated sapphire mateiral surface is shifted from at least +50 nm or at least -50 nm from the dominant wavelength, λ DU, of the reflected colour of the untreated sapphire material surface.