Ettringite - image 1
Ettringite - image 2
specimen video

Ettringite

Unknown Owner
Excellent large group of sulfur-yellow Ettringite crystals to 5 cm on minor matrix from the N’Chwaning II Mine in South Africa. The crystals are in fine condition with good color, and are quite large for the species. An exceptional ettringite for the N’Chwaning II Mine, from the Proctor Family Trust Collection. See the recent article in Rocks & Minerals Sep/Oct 2024 for more information on this rare species.

Product details

Species
EttringiteAbout Ettringite →
SizeSmall Cabinet
Dimensions3.5 x 5.8 x 6.2 cm
Added on09/25/2025
Locality
South Africa, Northern Cape, N'Chwaning II MineRegional guide →

Known provenance

DateCollectorAcquisition price
01/2026Unknown Owner$6,500.00
—Collector’s EdgeNot disclosed

Learn more

Ettringite
Mineral guide
Learn about Ettringite
lemon-yellow hexagonal prisms; a fragile hydrated sulfate with notable localities like Kalahari and Eifel, Crestmore, prized by collectors.
Ettringite
Regional guide
Ettringite from N'Chwaning II Mine, South Africa
N'Chwaning II ettringite is one of the great paradoxes of modern mineral collecting: a soft, water-rich cement-mineral species that, at this locality, became a cabinet-level showpiece. The best examples are lemon- to sulfur-yellow, glassy to silky, and sharply hexagonal, often with the kind of saturated yellow that collectors more readily associate with sulfur than with a calcium aluminum sulfate hydrate. On fine crystals the color is not a surface stain but an internal glow, especially in translucent prisms where the broad hexagonal faces show growth zoning, fine striations, and a waxy-gemmy brightness.