According to Jenkins, "the minerals of Alum Cave, contiguous to each other, include alum [mostly hair salt (?); see below], epsom salts [epsomite], saltpeter [?], magnesia , and copperas [melanterite]." Many tons of alum and epsom salt had accumulated.
Minute amounts have been found as tiny crystals in masses of hair salt in the soil.
Slavikite, a rare (or rarely identified) mineral worldwide, appears to form near the surface of masses of mixed hair salt and epsomite, and is probably produced by a reaction such as that below:
28Mg[SO.sub4]*7[H.sub.2]O + 20Fe[A1.sub.2][([SO.sub.4]).sub.4]*22[H.sub.2]O + 5[O.sub.2] + 4[Na.sup.+] epsomite halotrichite in hair salt
Small yellow and white masses of iron sulfates might be noticed on a few rock faces and in crevices and white masses of (mostly) epsomite and hair salt project locally from the ground, but most of the salts are in masses beneath the surface, to be seen only with some small amount of excavation (a few centimeters).
20Mg[A1.sub.2][([SO.sub.4]).sub.4]*22[H.sub.2]O + 50[H.sub.2]O + 4[H.sup.+] pickeringite in hair salt
Apjohnite occurs commonly as clear needles and silky masses of typical hair-salt appearance; most specimens of hair salt were identified as magnesian apjohnite by semiquantitative analysis with SEM/XRF (most analyses higher in Mn than Mg, with little or no Fe).
9) associated with hair salt. Mg, Fe, and S were detected by SEM/XRF in approximately 1:1:2 ratio.
Some is in radiating masses embedded in hair salt. Most crystals are pale pink under incandescent lights, pale blue-gray under fluorescent light, and nearly colorless in sunlight (alexandrite effect, due to cerium); a few are cream-colored.
Epsomite is often found intergrown with hair salt. It was originally identified by taste and distinctive habit, and by its unstable nature; the identification was confirmed by SEM/XRF.
It was originally identified as hair salt by silky fibrous appearance and astringent taste, but is distinguished from other hair salts by its common association with melanterite.