Shetland has some of the best preserved archaeology in Europe, owing to the lack of trees and abundance of stone.
There is evidence that the islands' inhabitants have made extensive use of the rocks and mineral resources since the islands were first settled about 6000 years ago.
The diversity of Shetland’s rocks and minerals has provided island residents with a variety of resources for a wide range of uses.
Quartz was an invaluable substitute for the flint used to create arrowheads in other parts of Britain and Europe during the Mesolithic. Beautiful felsite was used in the Neolithic to make polished weapons for ceremonial purposes.
In the Bronze Age, rocks of all kinds were heated in fires then used to heat large quantities of water at burnt mound sites found throughout the islands.
Later, Iron Age builders throughout Shetland exploited whatever stone was locally available to build over 100 stone towers or brochs. Sandstone is undoubtedly the most suited to the purpose – as testified by the broch of Mousa, still standing to almost its original height.
More recently, Viking and Norse inhabitants quarried the easily carved and versatile soapstone to make a number of vital domestic items including bowls, bakeplates, loomweights and fishing weights.
In the 19th and 20th centuries, limestone was roasted to create lime for building and agricultural purposes. Today the process of exploitation continues with numerous quarries producing talc, sandstone for roadstone and various crushed rocks for concrete and other uses.
Shetland’s metal ores have been exploited for over 2,500 years, with archaeological excavations frequently turning up evidence of metal working.
Throughout the Bronze and Iron Ages and into the Viking era, peat bogs were a source of impure iron deposits or ‘bog iron’ which formed when iron salts dissolved in groundwater reacted with air. Bog iron was smelted to produce tools and weapons.
However, the main period of metal-ore mineral exploitation was the 19th century when copper, lead, zinc, chromium, and magnetite were all extracted. Copper and iron mines were worked in southern parts of Shetland between about 1790 and 1920, the most notable being the Sand Lodge mine in Sandwick, although 15 tonnes of copper ore was also removed from Copper Geo on Fair isle.
About 10,000 tonnes of magnetite was mined near Sullom Voe between 1954 and 1957 with an estimated 20,000 tonnes still remaining. Still further north chromite deposits were extracted from opencast quarries on the island of Unst – some 50,000 tonnes between 1820 and 1944.
Semi-precious stones such as garnets can be found within Shetland’s metamorphic rocks, while traces of gold and platinum are known to occur in the North Isles.