Plattnerite
Chemical formula: Pb<sup>4+</sup>O<sub>2</sub>
Plattnerite is a rare lead oxide with a strong, almost metallic luster and very high density, most often forming black, reniform or earthy aggregates.
Properties
- Mohs hardness
- 5.5
- Luster
- Metallic to adamantine
- Streak
- Chestnut brown
- Density
- 9.4 - 9.7
- Cleavage
- Good on {110}
- Fracture
- Uneven to conchoidal
- Transparency
- Opaque, translucent on edges
- Crystal system
- Tetragonal
Diagnostic features
## Identification The most important diagnostic features of plattnerite are its very high density (the specimen feels unnaturally heavy for its size), chestnut-brown streak, and strong, almost metallic luster. Its occurrence in the oxidation zones of lead ore deposits is also a key indicator. ## Distinguishing from Similar Minerals Plattnerite is sometimes confused with other black, massive oxides, such as goethite, psilomelane, or tenorite. However, goethite has a yellowish-brown streak and is significantly lighter. Manganese oxides (psilomelane group) have a black or dark brown streak and are also lighter. Tenorite (copper oxide) has a grayish-black streak and is less dense. ## Crystal Forms Crystals are extremely rare, usually microscopic in size. They take the form of short prismatic or acicular columns with a square cross-section. It is much more commonly found as massive, reniform, botryoidal, or radial aggregates, as well as coatings and earthy masses.
Geological environment
## Genesis Plattnerite is a typical secondary mineral, forming in the oxidation (weathering) zones of ore deposits containing lead minerals, such as galena. It forms under strongly oxidizing conditions, often in dry, desert climates, where it replaces primary lead sulfides or other secondary minerals, e.g., cerussite. ## Mineral Associations This mineral often co-occurs with other minerals from the oxidation zone. Its most common associations include: cerussite, anglesite, smithsonite, hemimorphite, pyromorphite, wulfenite, as well as iron oxides (goethite, hematite) and manganese oxides. ## Localities The most important plattnerite localities worldwide include mines in Idaho (e.g., Bunker Hill Mine in Kellogg) and New Mexico in the USA. It is also known from Leadhills in Scotland (type locality), the Tsumeb Mine in Namibia, Broken Hill in Australia, as well as various locations in Iran, Mexico, and Greece.
Rarity
Rare
For collectors
## Quality Criteria The most prized specimens by collectors are those with well-formed crystals visible to the naked eye, which is extremely rare. Rich, lustrous reniform or botryoidal aggregates on a contrasting matrix, e.g., on white cerussite, are also highly valued. The purity of the specimen and the absence of damage are crucial. Even massive but well-formed aggregates with a strong luster are sought after. ## Popular Localities The best specimens in the world are considered to come from mines in the Coeur d'Alene region in Idaho, USA, especially from the Bunker Hill Mine, which has yielded excellent crystals and lustrous aggregates. Specimens from Scotland have historical significance, and interesting mineral associations have been found in Tsumeb, Namibia.
Care and storage
## Cleaning Plattnerite specimens should be cleaned very carefully, using a soft brush to remove dust. If necessary, distilled water can be used, but prolonged soaking should be avoided. Always dry the specimen thoroughly after cleaning. ## What to Avoid Plattnerite is sensitive to acids, which can damage it. Contact with household and laboratory chemicals should be avoided. As a lead-containing mineral, it is toxic – avoid inhaling dust and wash hands after each contact with the specimen. ## Storage Specimens should be stored in separate, sealed boxes or display cases to prevent abrasion and potential dusting. Due to lead's toxicity, it should be kept out of reach of children and pets. It does not require special lighting or temperature conditions.