Pauladamsite
Chemical formula: Cu²⁺₄(Se⁴⁺O₃)(S⁶⁺O₄)(OH)₄(H₂O)₂
Pauladamsite is a very rare, secondary copper mineral of intense blue color, occurring as microscopic, bladed crystals.
Properties
- Mohs hardness
- 2
- Color
- green
- Luster
- Vitreous
- Streak
- pale green
- Density
- 3.535
- Cleavage
- {001}
- Fracture
- Irregular/Uneven
- Transparency
- Transparent
- Crystal system
- Triclinic
Diagnostic features
## Identification Pauladamsite is identified based on its characteristic, intense blue color, crystal habit (fine, bladed or acicular), and specific occurrence environment. Co-occurrence with other secondary copper and selenium minerals is key. Final identification requires advanced analytical methods, such as Raman spectroscopy or X-ray diffraction. ## Distinguishing from Similar Minerals It can be confused with other intensely blue, secondary copper minerals, such as linarite, azurite, or cyanotrichite. It differs from linarite by its lighter shade of blue and lack of reaction with hydrochloric acid. It differs from azurite by its crystal habit (azurite usually forms tabular crystals or granular aggregates and reacts with acids). It differs from cyanotrichite by the absence of a silky luster and a slightly different form of aggregates. ## Crystal Forms Crystals are very small, bladed, elongated along one axis, with a maximum length of up to 1 mm. They most often form radial aggregates, rosettes, as well as dense, tangled masses.
Geological environment
## Genesis Pauladamsite is a secondary mineral that forms in the oxidation (weathering) zone of polymetallic deposits. It forms as a result of reactions between solutions rich in copper, sulfates, and selenates with primary minerals. Its presence is associated with the weathering of copper sulfides and selenides in an oxygen-rich environment. ## Mineral Associations This mineral occurs in association with other secondary minerals. In the type locality (North Star Mine), it was found in association with gypsum, jarosite, chalcomenite, linarite, malachite, azurite, brochantite, anglesite, as well as rare selenates such as schmiederite and munakataite. ## Localities The only confirmed and described locality of pauladamsite in the world is its discovery site – the dumps of the North Star Mine, in the Tintic mining district, Juab County, Utah, USA.
Rarity
Very rare
For collectors
## Quality Criteria The quality of pauladamsite specimens is primarily assessed based on the richness and aesthetics of the crystalline aggregates. Specimens with clearly formed, radial rosettes of intense blue color, contrasting with the rock matrix, are most valued. The size of the crystals, although always microscopic, is also important – the larger and better-formed the needles or blades, the more valuable the specimen. Association with other rare minerals is also important. ## Popular Localities The only source of specimens is the type locality in Utah, USA. All pauladamsite available on the collector's market comes from this single location.
Care and storage
## Cleaning Pauladamsite specimens are extremely delicate and brittle. Mechanical cleaning, including the use of brushes, should be avoided. If absolutely necessary, compressed air can be carefully used from a safe distance. Cleaning in water, especially ultrasonic cleaning, is highly inadvisable. ## What to Avoid Avoid contact with all chemicals, acids, and detergents. The mineral is sensitive to high temperatures and sudden temperature changes. As a hydrated mineral, it may be sensitive to changes in humidity and should not be stored in an overly dry environment. ## Storage It is recommended to store specimens exclusively in specialized micromount boxes, which protect them from mechanical damage, dust, and humidity fluctuations. Avoid exposure to direct sunlight.