Philolithite
Chemical formula: Pb²⁺₁₂O₆Mn²⁺₇(S⁶⁺O₄)(CO₃)₄Cl₄(OH)₁₂
Philolith is a rare mineral with a complex chemical composition, forming characteristic, hexagonal crystals of an intense red color.
Properties
- Mohs hardness
- 3-4
- Color
- Pale to medium apple-green
- Luster
- Adamantine
- Streak
- White
- Density
- 0
- Cleavage
- Perfect on {0001}
- Fracture
- Conchoidal
- Transparency
- Opaque
- Crystal system
- Tetragonal
Diagnostic features
## Identification Philolith is recognizable by its unique combination of features: intense red color, hexagonal habit of tabular crystals, high luster (submetallic to adamantine), and occurrence in association with minerals from Långban. A red streak is also an important diagnostic feature. ## Distinguishing from Similar Minerals Minerals such as zincite, kermesite, or realgar may have a similar color but differ in crystal habit, hardness, and environment of occurrence. Zincite has an orange-yellow streak, and realgar is much more light-sensitive. The characteristic hexagonal form of philolith is key in distinguishing it from other red minerals. ## Crystal Forms Philolith crystallizes as thin, tabular crystals with a hexagonal outline. These crystals often occur in rosette-like or imperfect, subparallel aggregates on the surface of the host rock.
Geological environment
## Genesis Philolith forms in metamorphosed iron and manganese ore deposits. It is a product of hydrothermal or metamorphic processes occurring in a unique chemical environment rich in lead, manganese, chlorine, and carbonates. ## Mineral Associations This mineral co-occurs with other rare minerals characteristic of Långban-type localities. It is most often found in association with calcite, barite, hausmannite, magnetite, native lead, and various serpentine group minerals. ## Localities The only confirmed locality for philolith in the world is the Långban mine in Filipstad municipality, Värmland region, Sweden. This is the "type locality" for this mineral.
Rarity
Very rare
For collectors
## Quality Criteria The most valued philolith specimens are those with well-formed, sharply terminated crystals of intense red color and strong luster. The aesthetic arrangement of crystals on the rock matrix and the absence of damage are also important. Contrast with bright calcite or barite significantly enhances the visual appeal of the specimen. ## Popular Localities As philolith occurs exclusively in Långban, Sweden, all collector specimens come from this single, historic locality. The mine has been closed since the 1970s, meaning no new specimens are entering the market, and available ones come solely from old collections.
Care and storage
## Cleaning Philolith specimens should be cleaned only very carefully, using a soft brush to remove dust. Due to its brittleness and softness, any contact with water or other chemicals should be avoided. Mechanical cleaning is highly risky. ## What to Avoid Contact with water, acids, and other cleaning agents that could chemically damage the mineral must be absolutely avoided. It is sensitive to scratches and mechanical damage. It should be protected from high temperatures and sudden temperature changes. ## Storage Philolith specimens should be stored in stable conditions, in sealed containers or display cases, to protect them from dust and physical damage. It is best to store it in its original "micromount" box, away from other minerals that could scratch it.