White apexite crystals (IMA 2015-002) associated to yellow cejkaite from the type locality for apexite in Apex mine (Reese River, Lander County, Nevada, United States of America). — Photo: David Hospital · CC BY-SA 4.0
Apexite
Apexite is an IMA-recognized mineral species in the phosphate class, with the chemical formula NaMg(PO₄)·9H₂O.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Struvite structural group.
Key properties: Mohs hardness 2; specific gravity 1.74; White streak; Vitreous to satiny luster.
IMA symbol Ape, IMA status: approved, named in 2015.
Secondary mineral, formed as efflorescent crusts on mine walls by the oxidative weathering of a uranium deposit by meteoric water.
It is found associated with Andersonite, calcite, čejkaite, gaylussite, goethite.
The name refers to the mine that produced the first samples.