Spectrolite

Spectrolite is the labradorite that comes from the Ylämaa area of south-eastern Finland. On a black or dark grey background it shows a strong play of colour that runs through almost every colour of the spectrum as the stone is turned, which is where the name comes from. It was found in 1940, during the Second World War, while the Salpa Line fortifications were being built. It has been used both as a cabochon and jewellery stone and, in large blocks, as a building and monument stone.

Jewellery: The most colourful pieces are made into cabochons, beads and small ornaments. The first workshop in Ylämaa to cut and polish spectrolite for jewellery opened in 1973. Building and monument stone: The dark, spectrolite-bearing rock has been quarried in large blocks and sold as “granite”, and used for facade cladding, walls, gravestones, sculpture, stairs, flooring and kitchen worktops. It was sold to Italy, China, Russia, Taiwan, Japan and the United States under trade names such as Gem Spectrolite, Arctic Blue and Finlandia Blue.

It has a hardness of 6–6.5 on the Mohs scale. It can scratch glass; a steel knife scratches it only with difficulty. Its specific gravity is 2.68–2.72 g/cm³.

Its best-known localities: Ylämaa (Ylijärvi, Mättö and Pahaoja quarries), Lappeenranta, South Karelia, Finland.

The background is black or dark grey; the play of colour is seen only from certain angles and, besides blue and green, can include yellow, orange, red and violet. In worked pieces of the rock, a coarse-grained black background holds glittering, iridescent labradorite crystals from 0.5 to 15 cm across, with whitish patches of plagioclase here and there. A good share of Finnish spectrolite shows a cat's-eye effect as well as the play of colour.

On the “street to diamond” value ladder it sits on step 6 of nine: Fine ornamental and collector stone. What matters most is how wide and lively the play of colour is: pieces in which the colour covers the whole face and shows yellow, orange, red and violet as well as blue and green are the most sought after. A cut parallel to the coloured layers, freedom from cracks and an extra light effect such as a cat's eye add value. Documented Ylämaa origin matters, because the name is also used for labradorite from elsewhere. As a building stone, block size, even distribution of colour and how well it takes a polish are what count.

Crystal-therapy websites claim that spectrolite is linked to the “third eye chakra”, supports intuition and spiritual growth and shields its wearer from “negative energies”. The same sources claim that spectrolite soothes the nervous system, eases stress, anxiety and depression and boosts vitality. Spectrolite's striking colours are a physical effect produced when light interferes in extremely thin feldspar layers inside the stone; there is no scientific evidence that it strengthens intuition, protects anyone or affects the nervous system. Anxiety and depression are treatable conditions; they call for a doctor or a mental health professional, not a stone. This section reports beliefs; it is not health information. There is no scientific evidence for these claims and no stone replaces medical treatment.