Dugganite
Chemical formula: Pb<sup>2+</sup><sub>3</sub>Zn<sup>2+</sup><sub>3</sub>(Te<sup>6+</sup>O<sub>6</sub>)(As<sup>5+</sup>O<sub>4</sub>)<sub>2</sub>
Dugganite is a rare lead and zinc arsenate and tellurate, forming small, hexagonal crystals with a vitreous luster and a light green color.
Properties
- Mohs hardness
- 3
- Luster
- Vitreous
- Streak
- White
- Density
- 6.33
- Cleavage
- None
- Fracture
- Uneven
- Transparency
- Transparent to Translucent
- Crystal system
- Trigonal
Diagnostic features
## Identification Amateur identification of dugganite is difficult due to the small size of its crystals. Key features include its light green color, hexagonal crystal outline, vitreous luster, and co-occurrence with other secondary lead and zinc minerals in oxidation zones. Definitive identification requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS). ## Distinguishing from Similar Minerals Dugganite can be confused with other green, secondary arsenic minerals, such as mimetite, conichalcite, or olivenite. It is distinguished from them by its hexagonal crystal form and a specific geochemical environment rich in tellurium. It often occurs in paragenesis with cheremisinitem, which is its arsenate analog. ## Crystal Forms Dugganite crystallizes in the form of short, hexagonal prisms or thicker, tabular crystals. It often forms radial aggregates, rosettes, or spherulitic clusters composed of tiny, acicular crystals.
Geological environment
## Genesis Dugganite is a secondary mineral that forms in the oxidation zones of hydrothermal polymetallic deposits rich in lead, zinc, arsenic, and tellurium. It forms as a result of the weathering of primary sulfides and tellurides under conditions of low temperatures and pressures. ## Mineral Associations This mineral often co-occurs with other rare secondary minerals. Its typical associations include: cheremisinitem (its phosphate analogue), quartz, galena, sphalerite, chalcopyrite, tennantite, as well as rarer tellurates and arsenates such as emmonsite, teinite, kankite, beudantite, segnitite, anglesite, and cerussite. ## Localities The most important and type locality for dugganite is the Emerald Mine in Tombstone, Arizona (USA). It is also known from several other localities worldwide, including the Trixie Mine in Utah (USA), the Moctezuma Mine in Mexico, the Kawazu area in Japan, and the Clara Mine in the Black Forest, Germany.
Rarity
Very rare
For collectors
## Quality Criteria For collectors, the most desirable specimens are those with well-formed, sharp crystals of intense green color. Rich crystalline aggregates, especially rosette aggregates that stand out clearly from the host rock, are highly valued. Due to the microscopic nature of most specimens, the quality of the crystal itself, rather than its size, is key. Association with other rare minerals also enhances its attractiveness. ## Popular Localities The best and most classic dugganite specimens, serving as the type material for this mineral, come from its type locality – the Emerald Mine in Tombstone, Arizona. Specimens from other known localities, such as the Trixie Mine in Utah or Moctezuma in Mexico, are also sought after by specialists.
Care and storage
## Cleaning Specimens should be cleaned very carefully, using a soft brush to remove dust. Due to its softness and brittleness, ultrasonic cleaners and strong streams of water should be avoided. If liquid is necessary, distilled water is recommended. ## What to Avoid Avoid contact with acids and other chemicals that can damage the mineral. Dugganite is brittle, so it must be protected from impacts and scratches. As a lead and arsenic mineral, it is toxic – avoid inhaling dust and wash hands after each contact. ## Storage Dugganite specimens, especially microscopic ones, are best stored in sealed "micromount" boxes, which protect them from dust and mechanical damage. It should be stored away from moisture and at a stable temperature.