Made from the dried stigmas of the Autumn crocus, there are only three stamens to a flower. Taking about a quarter of a million flowers to yield one pound of dyestuff, it is the world's most expensive dye product. Saffron is an Arabic word, the Greeks calling it krokos, the Roman's crocus. There is no Gaelic word for it, although one was invented in the early eighteenth century, out-with Ireland. It is not indigenous to the British Isles and would have had to be imported, thus making its consumption there prohibitive, especially since the Irish leine is known to have taken about 24 yards of material in its construction. It would be less expensive to have a shirt made of pure gold than dyed from saffron! It seems therefore in the ancient world to have meant the colour yellow rather than a dye stuff, and that it was a pure bright yellow.

The first to mention saffron in the ancient world was Pliny, who referred to it as an agent to combat lice. The next was an early thirteenth century reference to its use in Ireland and Iceland for the same purpose by the English Doctor Gilbertus Anglicus. Until this day, there is a strong tradition in Iceland that ancient garments there were coloured yellow. There is also a tradition today in Ireland that the yellow colour was obtained from heather tops, rock lichen and bog myrtle. The first clear Irish derivation of the colour yellow is given in a ca. 1566 account by an English Jesuit, one Father Good, a school master in Limerick who describes ; "with the boughs, bark and leaves of poplar trees beaten together they dye their loose shirts of a saffron colour ". Bog water has a great deal of oak dissolved in it and its tannin would also yield a yellow colour.

The first Gaelic reference to the yellow coloured shirt was in 1703, written by Martin Martin a Scot of the Hebrides in his "Description of the Western Isles of Scotland". He invents the word 'croich' and 'croch' apparently in an attempt to Gaelicise the Latin word crocus in describing the yellow colour of shirts as "leni croich". The Gaelic word for lichen is crotal and Martin seems to have forgotten this word since he tells us that the garment had fallen out of use in his area as early as 1600.

There were others who mentioned saffron in their written accounts regarding Ireland. They were all foreigners to the Gaelic way of life, French, Italians and English. Since we have not a single Irish or Highland reference to the use of saffron, it is safe to conclude that the term was used to describe the colour of the garment, not the stuff with which it was dyed. It is perhaps as similar as a reference to an orange shirt, whose dye has nothing to do with the citrus fruit.