Romancheite with Hollandite

specimen number:
2062492

location:
Nancy Mine, Socorro Co., New Mexico, USA

description:
Very choice example for this classic material, velvety black crystal groupings of what is often called psilomelane across the top of matrix. These are aesthetically arranged and in great condition. This is mostly a mixture of romancheite and hollandite which has been confirmed.

The Nancy Mine, also known as the Tower Mine, is located in the Luis Lopez Manganese District of Socorro County, New Mexico. Mining operations in the district began during the First World War and continued sporadically until the early 1970s. Geologically, the area is situated within the northern Chupadera Mountains, where hydrothermal veins formed within welded volcanic tuffs along complex fault and fracture zones related to regional rifting and volcanic activity.

Hollandite and romanecheite are hard, dark manganese oxide minerals that commonly occur together in compact or botryoidal masses. Historically, when these distinct minerals and related oxides are mixed closely together without visible individual crystals, the resulting aggregate is referred to by the traditional group name psilomelane. This material is characterized by a smooth, shiny surface, a submetallic luster, and a dark brownish-black streak, frequently appearing as a secondary mineral within oxidized zones of manganese deposits.

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