Abstract: In the Artikutza area, near the contact with the southern Aya granite, skarns containing hedenbergite, grandite, epidote, quartz, calcite, actinolite, idocrase and magnetite occur and have been found to contain ilvaite layers. This is the second reported occurrence of ilvaite in Spain; spectral reflectances, colour values. Vickers hardness numbers and chemical composition are given. The monomineralic ilvaite lens intercalation developed by hydrothermal alteration of hedenbergite in a second stage of skarn formation.