New Mexico Mineral Symposium — Abstracts

The Rex and Smuggler, Petroglyph, and Macy's mines of the Hillsboro district have been fairly well known mineral collecting localities for several years.

Good specimens of Willimite (Zn₂SiO₄), Wulfenite (PbMoO₄), Vanadinite (Pb₅(VO₄ )₃Cl), endlichite (Pb₅[(AS,V)O₄]₃Cl), melanotekite (Pb₃Fe₄Si₃O₁₅) and calcite (CaCO₃ ) have been found on the dumps and in the workings of these mines. At the Macy's mine endlichite and calcite are found scattered throughout the underground workings. Several high quality specimens were obtained here at the turn of the century and are now in the collections of the Smithsonian Institute. The Rex and Smuggler group of prospects are one of the few places in the United States where willimite occurs. The willimites are found as short prismatic to tabular, colorless crystals and as crusts of unusual needle-like crystals. Melanotekite also occurs at this group of mines as small (=.5 mm) orthorhombic crystals in cavities of brown jasperoid. This is the second known world occurrence of melanotekite.

The Petroglyph or Miners Dream claim is known for its small pockets of wulfenite and vanadinite crystals. The wulfenites are found as rough crystal clusters and as single, thin, square tabular crystals, sometimes coated with chalcedony. The red-orange vanadinites occur as small hexagonal prisms with smooth faces and sharp edges. Occasionally the crystals occur as hollow prisms.

The Petroglyph and Macy's mines are presently under claim. Permission to collect should be obtained from the owners before entry. The Rex and Smuggler group are open for collecting.