Eudialyte: Properties, Facts and Photos
What is Eudialyte?
Eudialyte is a rare complex silicate mineral that belongs to the eudialyte group, which is known for its striking colours and unusual crystal structures. It's composed primarily of sodium, calcium, cerium, iron, manganese, zirconium, and niobium, among other chemical elements.
Eudialyte (pronounced you~die~a~lite) comes from the Greek words 'eu', meaning 'well' and 'dialytos', meaning 'decomposable.' This refers to the fact that its crystals decompose particularly well in acids and, in some cases, dissolve completely.
Eudialyte was first described in 1819 in Greenland by German professor of chemistry Friedrich Stromeyer.
Eudialyte has an unusually complex structure, so the location where it's found can help with correct identification. It can include a wide range of chemical elements, with some studies reporting more than 40 across the entire group of eudialyte minerals.
Eudialyte occurs in alkaline igneous rocks, which are formed from magma rich in alkali elements such as potassium and sodium. It's often associated with other minerals such as feldspar, nepheline, aegirine and zircon.
Eudialyte forms in the late stages of crystallization as magma cools and solidifies. It's mined primarily in Mount Saint Hilaire, Canada, and the Kola Peninsula, Russia, but can also be found in Greenland, Norway, Arkansas, and the USA.
In the following photo, just the reddish-coloured crystals are eudialyte.
Eudialyte contains zirconium as one of its constituent elements. The amount is relatively small so it's not economically viable to extract it on a large scale. The mineral zircon is a more abundant and commercially important source of zirconium.
Zirconium is a lustrous, greyish-white metal highly resistant to corrosion, heat and wear. It has many highly desirable properties, so is widely used in industry.
Eudialyte is valued as a mineral specimen and gemstone due to its unique and attractive colours. Collectors appreciate it for its aesthetic qualities rather than its importance as an ore of zirconium.
Eudialyte grades 5 to 5.5 on the Mohs scale of mineral hardness.
'Almandine spar' has apparently been used as an alternative name for eudialyte but there's very little information available on the origins of this name. There is no connection between the mineral eudialyte and the variety of garnet known as almandine. Garnet and eudialyte are different minerals.
Article Pictures
The pictures in our article are clickable and redirect to the original photo.
The mineral at the top is agpaite with inclusions of eudialyte. It comes from Nyorkpakhk Mountain, north of the Vuonemmiok River, west-central Kola Peninsula in the far north-west of Russia. Photo courtesy of James St.John.
Pop-up photos: Nepheline and zircon: Courtesy of James St.John. Almandine garnet: Courtesy of Stan Celestian.
