Gatelite
2 in the gallery
Gatelite is a rare calcium cerium magnesium aluminum silicate mineral that forms in pegmatites under highly aluminous, peralkaline conditions. It typically grows as elongated, prismatic crystals and may exhibit a glassy to resinous luster, often with a pale to medium brown color that can show subtle zoning. The mineral’s structure features silicate groups that contribute to its distinctive, complex composition, and its rarity makes each specimen a noteworthy find for a thoughtful collector.
- Formula
- CaCe3(AlAl2Mg)[Si2O7][SiO4]3O(OH)2
- Rarity
- Ultra Rare
- Stability
- Stable
- Collector interest
- High Interest
- Classification notes
- Sorosilicate; epidote supergroup, gatelite subgroup
Key characteristics
- Crystal system
- monoclinic
- Mohs hardness
- 6
- Specific gravity
- 4.15–4.17
- Luster
- vitreous
- Transparency
- transparent, translucent
- Color
- brown, yellow
- Streak
- white
- Fracture
- uneven
- Crystal habit
- prismatic, tabular, granular
- Micro-mount only
About Gatelite
Notable specimens have come from a few specialized localities known for ultra-rare rare-earth bearing phases. Where it occurs, gatelite tends to be associated with other uncommon pegmatite minerals, and pieces may display fine crystallization, expressive termination faces, or a gentle, satin-like sheen that appeals to careful study and display. Collectors prize gatelite for its rarity, its rarity-driven curiosity, and its reminder of the diverse chemistry possible in pegmatitic systems. Each well-prepared specimen offers a window into the chemistry of alkaline environments and the intricate ordering of silicate minerals that emerge under those conditions.