Issue date: 29 May, 2020
MINERALS. JET
The famous Asturian jet is an organic gemstone, highly valued for its excellent cutting qualities, and attaining a typical shine and intense black colour after polishing. Specialist studies determine that the woody material, which becomes a humic carbon, peri hydrogenated during the Kimmeridgian age (Late Jurassic) around 155 million years ago, underwent particular circumstances while it formed, such as impregnation with hydrocarbons, which gives it some of its unique features and exceptional stability for use in jewellery making.
Although it is scarce in nature, there are sites for jet, and other similar materials, with various features, in various places on the planet. It was one of the first raw materials used by man and was, mainly, turned into objects for personal adornment and amulets. Some of the oldest pieces in Europe are conserved in Asturias including some beads which are around 19,000 years old. Magnificent gems made from jet, recovered from archaeological sites from various eras, are kept in museums worldwide
On the Iberian Peninsula there are other deposits which have also been exploited in the past, such as Teruel, which is Cretaceous origin, and in the area of Batalha (Portugal) which is also Jurassic in origin. However, it is the one located on the Asturian coast, and mainly the one in Oles (Les Mariñes, Villaviciosa), which, since the Middle Ages, mainly due to its early association with the Santiago Way, has been known for its excellent quality. Its prestige was valued for centuries by the Santiago de Compostela Jet Workers Guild, which demanded exclusive use of the Asturian jet for its workers in its Ordinances, thus protecting a rich monopoly. Pilgrimage souvenirs and symbols made from Asturias jet are kept in some of the more prestigious museums in the world. The pilgrimage to Santiago made Asturian jet universal.
Jet from Les Mariñes was also, for centuries, the subject of blooming business with America, where other similar local materials had already been in use since the Pre-Columbian Era. The last big commercial explosion for Asturian raw materials occurred between the end of the 19th century and the beginning of the 20th century. For years, hundreds of tonnes of material were exported to England as its historically famous jet, from Whitby (York), was insufficient to meet the high demand created by English Victorian fashion for mourning clothes. A good part of the prestigious, and still highly sought after, Victorian jewellery from Whitby was, in reality, made from Asturian raw materials.
There have been no operational mines in Asturias now for almost 100 years. It was, apart from the first few years of the 20th century, mainly extracted manually. The search for the material, in narrow tunnels, which were sometimes hundreds of metres long with several offshoots, was hard work entailing enormous sacrifice and risk. Craftspeople still working with the material today get supplies from cliff landslides, overseas suppliers and old spoil sites, witnesses to past glories which have almost run out.
In Spain, as well as in other international production centres, jet continues to be worked into traditional pieces for popular taste and also innovative designs and combinations which are more in line with modern taste.
The image shows one of the old abandoned mine entrances in the Oles area. This is the only one that can be visited and is the end of what is known as the “Jet Route” (PR-AS.199).
A small sample of the prestigious Oles jet is impregnated exclusively in this Premium Sheet.
Andrea Menéndez Menéndez
Has a degree in Geography and History. Expert in archaeology and heritage management and specialist in the study of jet from a historical and archaeological point of view.
Rate A - €0.75. For a “standard” letter or postcard within Spain, up to 20 g.
Rate A2 - €0.85. For a “standard” letter or postcard within Spain, between 20 g and 50 g.
Rate B - €1.65. For a “standard” Ordinary International letter or postcard addressed to Europe (including Greenland), up to 20 g.
Rate C - €1.75. For a “standard” Ordinary International letter or postcard addressed to the rest of the world (except USA, Canada, Japan, Australia and New Zealand), up to 20 g.
Rate D - €2.10. For a “standard” Ordinary International letter or postcard addressed to the USA, Canada, Japan, Australia and New Zealand, up to 20 g.