Eltyubyuite
Ca12Fe3+10Si4O32Cl6
A rare chlorine-bearing iron garnet-supergroup mineral, the ferric analogue of wadalite, formed in high-temperature combustion-metamorphic rocks.
- Mohs hardness
- 5-6
- Color
- greenish to yellow-brown
- Type
- mineral
Got a rock like this?
Identify any rock from a photo, free.
Overview
Eltyubyuite is a rare member of the garnet supergroup belonging to the wadalite group, in which chlorine and a different cation arrangement set it apart from common silicate garnets. It is essentially the ferric-iron analogue of wadalite, with calcium, ferric iron, silicon, oxygen, and chlorine.
It is greenish to yellow-brown and occurs as small crystals or grains in unusual high-temperature rocks. Its chlorine content and chemistry make it a notable curiosity within the garnet supergroup.
Eltyubyuite is named after its type locality in the Eltyubyu area of the northern Caucasus, Russia.
Formation & geology
Eltyubyuite forms at high temperatures in calcium- and iron-rich, chlorine-bearing environments, specifically in pyrometamorphic (combustion- and contact-metamorphic) rocks. At the type locality it occurs in skarn-like and altered carbonate xenoliths affected by high-temperature processes.
The presence of chlorine in the structure requires a halogen-rich fluid or melt at the time of crystallization.
It is associated with other high-temperature calcium silicates and is part of mineral assemblages similar to those in some combustion-metamorphic and larnite-bearing rocks.
How to identify it
Look for small greenish to yellow-brown grains in high-temperature, calcium-rich pyrometamorphic or skarn rocks. Hardness is around 5-6, softer than common silicate garnets, reflecting its distinct wadalite-group chemistry.
Eltyubyuite cannot be reliably identified by eye; it is confirmed by chemical and X-ray analysis showing its chlorine content and ferric-iron-dominant composition. Its unusual geologic setting distinguishes it from ordinary andradite or grossular.
Uses & significance
Eltyubyuite has no commercial or gem use. It is a rare research and collector mineral, valuable for understanding the diversity of the garnet supergroup and the role of chlorine and high-field-strength elements in garnet-type structures.
Specimens are of interest mainly to advanced collectors and mineralogists studying combustion-metamorphic and pyrometamorphic assemblages. It has no metaphysical tradition.
Frequently asked questions
What makes eltyubyuite unusual?
It belongs to the chlorine-bearing wadalite group of the garnet supergroup, unlike ordinary silicate garnets, and is the ferric analogue of wadalite.
Where was eltyubyuite found?
In high-temperature pyrometamorphic rocks of the Eltyubyu area in the northern Caucasus, Russia.
Is eltyubyuite a true garnet?
It is a member of the broader garnet supergroup, though its chlorine-rich chemistry differs from common silicate garnets.
Can eltyubyuite be used as a gem?
No. It is rare, small-grained, and softer than typical garnet, of interest only to scientists and collectors.
Eltyubyuite guides
In-depth guides for identifying, valuing, and understanding Eltyubyuite.
