View source for Lapis lazuli

''Lapis'' is a semi-precious [[gemstone]], known and used as far back as Pharonic [[Egypt]].  It is a compound of various other minerals and, in its finest form is intense radiant blue, occasionally with golden pyrite flecks.  It takes excellent polish and has been widely used for [[jewellery]], and in [[mosaics]].  Ground, it is a major constituent in the pigment ''Ultramarine''.

Accordingly it '''is''' a period [[stone]], and '''was''' available in [[medieval]] [[Europe]].