Ireland produced gems of many kinds - more or less valuable - which were either worn as personal ornaments by themselves - cut into shape and engraved with patterns - or used by artists in ornamental work. Precious stones are often mentioned in ancient Irish writings. In Kerry were found -and are still found -" Kerry diamonds," amethysts, topazes, emeralds, and sapphires: and several other precious stones, such as garnet. were found native in other parts of the country. A pearl was usually designated by the word se/d [shade]: but this word, as we shall see in chapter xxiii., sect. 4, was also applied to a cow regarded as an article of value or exchange; and it was often used to designate a gem or jewel of any kind. Se/d is still in use in this last sense. Several Irish rivers were formerly celebrated for their pearls; and in many the mussels that produce pearls are found to this day - often with pearls in them.
Of the various ornaments worn on the person, the common necklace was perhaps the easiest in use. Necklaces formed of small shells are common among primitive people all over the world, and they have been found with skeletons under cromlechs in several parts of Ireland, of which specimens may be seen in the National Museum in Dublin, belonging to prehistoric ages. In historic times necklaces formed of expensive gems of various kinds, or of beads of gold, were in use in Ireland; and they are frequently mentioned in the tales and other ancient Irish records.