Blaenau Ffestiniog (pronounced bly-now fest-inny-oc) is the capital of the Welsh slate quarrying industry. The slate-bearing strata of Ffestiniog belong to the Ordovician or Lower Silurian systems, and are of a uniform soft blue-gray color, although the North Vein or topmost bed shows a tendency to be slightly darker. The chemical analysis of a standard Ffestiniog slate shows silica 55%, alumina 25%, iron oxide 11%, the remainder being composed of various elements of which the chief is magnesia. The lime contents - an excess of which often characterizes an inferior slate - are negligible.
Blaenau slate has been an important part of quality snooker and billiards tables for many years owing to the smooth flat surface that is revealed when slates are split or riven. During Victorian times a snooker table would comprise four large blocks of slate, each 3 inches thick, so that they could be disassembled and carried by pack horses for the pleasure officers in the British Colonial Army on patrol in the north-west frontier in India. It was said, that along with his rifle, every serving officer took his snooker cue up the Khyber Pass. Due to the lower quality of the remaining slate from the mine however, modern tables have to be assembled from five slabs.
The slate produced from the Blaenau area is one of the highest quality roofing slates in the world, and gives the houses in Wales their characteristic blue roofs. Slate was mined via a variety of methods in the 19th century and all of these have left their mark on Blaenau, with the entire town and much of the surrounding countryside being blighted with slag heaps of slate spoil. Despite being in the centre of the Snowdonia National Park, the gray slag that surrounds the town prevents it from being officially included in the designated Park area. Current plans to deal with this slag are being challenged by an environmental pressure group 
The slate industry that Blaenau epitomizes is today only a fraction of its former size. In the 1880's the industry employed over 400 men. To say that these men were responsible for the today’s slag spoil is to misunderstand the history of Blaenau. Today the town has reinvented itself as a tourist destination with former quarries  offering trips on the miner's tramway into the side of the mountain and into the massive underground caverns created by the slate workers.
In preparations for the United Kingdom's millennium celebrations, the Welsh Development Agency (WDA) in conjunction with the Beautiful Blaenau campaign sponsored research into how the slag may put to use in an environmentally-friendly way. In 2001 the Welsh Aggregates Company launched a range of composite building materials that have been used extensively in the regeneration of Cardiff's historic waterfront. Indeed, traditional Welsh slags can now be found throughout Cardiff city center.
The mined slate was taken on the narrow gauge Ffestiniog Railway which links Blaenau Ffestiniog with Porthmadog on the coast. The Festiniog Railway Company is the world's oldest independent railway company, established in 1832 by Act of Parliament. The ride is spectacular as the line twists and turns its way through the Welsh countryside.
Blaenau also has another claim to fame, In 1940 when London was faced with intensive bombing by the Luftwaffe every night, Prime Minister Winston Churchill was very concerned for the safekeeping of Britain's art treasures and he issued an order for them to be moved from the museums and art galleries in London. In order to keep them safe, they were sent to Manod Quarry in Blaenau Ffestiniog.
- Map showing the Location of Blaenau Ffestiniog
- General Information: http://www.blaenauffestiniog.cymru.org/
- The Ffestionog Railway: Http://www.nwt.co.uk/english/snowdonia/blaenau_ffestiniog.htm
- Tourist information: http://www.walesdirectory.co.uk/Towns_in_Wales/Blaenau_Ffestiniog_Town.htm
- For a more detailed account, see: http://www.llechicymru.info/t000952.cymraeg.htm
- The Slate Waste Action Group (SWAG) opposes plans to transport the slag to the North Wales coast.
- See the website for the The Llechwedd Slate Caverns