Hedenbergite, or calcium iron pyroxene, is a black mineral closely allied to diopside and, owing to the isomorphous replacement of iron by magnesium, there is no sharp line of division between them.
The other minerals found in the concentrates are pebbles and fragments of pyrope, zircon, cyanite, chrome-diopside, enstatite, a green pyroxene, mica, ilmenite, magnetite, chromite, hornblende, olivine, barytes, calcite and pyrites.
The boulder is a crystalline rock consisting of pyroxene (chrome-diopside), garnet, and a little olivine, and is studded with diamond crystals; a portion of it is preserved in the British Museum (Natural History).
The pyroxenes may be pale green diopside, dark green aegirine-augite, or blackish green aegirine (soda iron pyroxene), and in many cases are complex, the outer portions being aegirine while the centre is diopside.
Many semi-precious and precious stones are found in Utah, including garnet (long sold to tourists by the Navaho Indians), amethyst, jasper, topaz, tourmaline, opal, variscite (or " Utahlite "), malachite, diopside and Smithsonite.