The remains of an early medieval metalworking workshop have been discovered on the Scottish island of Islay. It dates to between the 6th and 9th centuries A.D. The iron smelting facility was built over an earlier domestic building that had been abandoned. Metalworking waste, the upper part of a rotary quern, a bone needle and shale bracelet fragments were recovered from several of the features associated with the buildings. Shale bracelets are rare in the Inner Hebrides; these are the only examples known from Islay. The shale probably came from central Scotland. Over time a change in function took place, from domestic use to that with an industrial focus, which took place after the domestic building had fallen into a state of disrepair. In contrast to many known metalworking workshops from early medieval Scotland, which were often enclosed within royal or lordly strongholds, the Coultorsay workshop was a relatively modest structure. It appeared to have been used for smelting bog ore to extract iron bloom which could then be made into tools and weapons somewhere else. The building is figure-eight-shaped, delineated by overlapping curvilinear gullies, and measures 22 feet by 21 feet covering an area of 390 square feet. One of circular enclosures is larger than the other. The connected overlapping circles design is reminiscent of Pictish cellular buildings (round buildings or “cells” linked together). The abandoned dwelling that the metalworking workshop was built over may have been Pictish, or at least been influenced by Pictish architecture. During this period the island, along with the whole western seaboard of Scotland, was part of the Gaelic Kingdom of Dál Riata. It was defeated by the Picts in 741 and became their client kingdom, although the Pictish and Dál Riata crowns merged voluntarily and became the Kingdom of Alba in 900, under pressure from Viking raiders. Islay was taken by the Norse in the late 9th century. Very few early medieval structures have been found on Islay, and the sites that are known were ecclesiastical (a chapel, a burial ground), not domestic dwellings or industrial workshops. That makes this structure a unique testament to the day-to-day life and work of the people who lived on the island in the early Middle Ages.