The labradorite or spectrolite is a mineral of the group of silicates, subgroup tectosilicatos and within them belongs to the feldspars called plagioclase. It is an aluminosilicate of sodium and calcium. The synonym for spectrolite refers to the spectral iridescence that is typical of this mineral.
It is an intermediate member of the solid solution series of plagioclase, whose extremes are albite (sodium plagioclase) and anorthite (calcium plagioclase). For this reason, it is sometimes considered as a variety of anorthite.
Labradorite is named after its first location, the Labrador peninsula (Canada) . On its coast, the Czech missionary Father Adolf discovered it in 1770. It was first described in 1896 in the book of Edelsteinkunde (Gemology) by Max Bauer.
Labradorite is truly a beautiful and fascinating mineral. Apparently ugly, its charm is proven when we turn it to observe it from the right position until its brilliant iridescence flashes – what some call labradorescence for being so typical of it. It presents in these glitters a range of colors from blue to violet, sometimes with greens, yellows or oranges, depending on the variety, even some rare specimens show all these colors simultaneously.
It frequently presents twins, producing the twinned crystals an effect of thin layers piled up.
Appears in the form of well-formed crystals, elongated or tubular habit, implanted or twinned: are very frequent the twins of poly-synthetic type easily recognizable thanks to the presence of fine striations, which are governed by the laws of albeit and pericles, what differentiates them from potassium feldspar such as ortose.
It is formed in the crystallization of igneous rocks and metamorphic rocks. It is very common for Labradorite to appear in the gabros and in other igneous igneous rocks, since the general rule is that the plagioclases are more calcium the more basic the rock that contains them. It is the main component of the northeaster rock.
Due to its formation environment, the minerals to which it normally appears are biotite, pyroxene and hornblende.
Location, extraction and use
Notable deposits have been found in Labrador (Canada), where it was described, as well as in the Scandinavian peninsula.
Apart from the collection interest, labradorite has industrial applications for manufacturing ceramics, refractory materials and enamels, as well as cutting large slabs in the construction of buildings as an ornamental coating of the walls.
Some labradorites can be used in jewelry by polishing to make necklaces or labradorite wands.