It is the type locality for five mineral species (vauxite, metavauxite, paravauxite, sigloite and jeanbandyite) and has also produced some of the world's best specimens of stannite, cylindrite, monazite, bismoclite, and other species.
Pale orange, transparent, resinous masses of evansite, much resembling tree resin, are occasionally found in association with metavauxite.
It was the principal gangue mineral in some of the richest cassiterite veins mined in the 1920's, and is considered to be the precursor from which the extensive suite of other phosphates (vauxite, paravauxite, metavauxite, wavellite, variscite, crandallite, childrenite, vivianite and allophane) developed, except for monazite and xenotime.
Metavauxite was described by Gordon (1944) as being colorless, white, or pale greenish white.
Metavauxite always occurs on wavellite, which encrusts brecciated fragments of porphyry along faults cutting the veins.
Bandy (1944) noted that metavauxite is relatively abundant as loose silky masses in open fractures along a branch of the San Jose vein, on Level 446.
It has been found on crusts of blue vauxite in the fault zones, and as crystals perched on metavauxite needles.
However, on a branch of the San Jose vein on Level 446 Bandy (1944) found the reverse: metavauxite on vauxite.
Of particular interest are assemblages such as rose-pink monazite-tourmaline-cassiterite-quartz; complexly twinned red greenockite with wavellite; childrenite with vauxite, paravauxite, and wavellite; wavellite with fluorapatite; and vauxite with metavauxite.
Llallagua phosphates, including childrenite, crandallite, fluorapatite, metavauxite, monazite, paravauxite, sigloite, vauxite, vivianite and wavellite, were actively collected by Bandy.