Glauconite with Quartz Druzy
Glauconite (Phyllosilicate) with Quartz (var. Druzy Quartz) · Mineral Specimen / Sedimentary Geode Material
Crystal System
Monoclinic (Glauconite - micaceous flakes/pellets) and Trigonal (Quartz - hexagonal prism terminations)
Mineral Group
Silicates (Glauconite is a Mica-group Phyllosilicate; Quartz is a Tectosilicate)
Chemical Formula
(K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2 for Glauconite; SiO2 for Quartz
Formation Process
Sedimentary/Diagenetic: Glauconite forms on seafloors in marine environments with low oxygen; subsequent hydrothermal or groundwater activity precipitates the sparkling quartz druzy in voids.
About This Crystal
The specimen exhibits a dull, olive-to-forest green earthy matrix characteristic of Glauconite, partially covered by a fine layer of sparkling, colorless-to-white micro-crystalline quartz ('druzy'). The luster varies from earthy/dull in the green areas to vitreous/glittering on the crystal faces.
Physical Characteristics
Color: Green and grey/white; Streak: Light green to colorless; Cleavage: Perfect basal (mica-like) for glauconite, none for quartz; Fracture: Uneven/Conchoidal; Specific Gravity: 2.4-2.8; Fluorescence: Typically inert.
Optical Properties
Biaxial (-) high birefringence for glauconite; Uniaxial (+) for quartz. No significant pleochroism visible in this massive/druzy state. Refractive Index: 1.59-1.64 (Glauconite), 1.544 (Quartz).
Hardness & Durability
Origin Region
Common in sedimentary basins worldwide (e.g., Greensand formations in New Jersey, USA; Isle of Wight, UK; or Western Australian sedimentary deposits)
Hardness & Durability
Mixed: Glauconite is very soft (Mohs 2); Quartz druzy is hard (Mohs 7). The specimen is brittle and the sparkling crystals can be easily abraded or knocked off the soft matrix.
Care & Maintenance
Clean only with compressed air or soft brush; avoid water as it may penetrate the porous glauconite matrix and cause degradation. Store in a padded box away from harder minerals that could scratch the green surface.
Rarity & Value
Common as a mineral occurrence; low commercial value ($5-$25 for handheld specimens). Value is based primarily on the aesthetic contrast between the green matrix and the sparkling druzy.
Special Characteristics
Sparkling 'sugar' druzy effect; typical of marine sedimentary deposits; the green color is due to high iron (Fe3+) content within the silicate structure.
Lore & History
Historically used as a green earth pigment (Terre Verte) in Renaissance painting. In metaphysical lore, it is believed to be a 'grounding' stone associated with the Heart Chakra and the stabilizing energy of the ancient sea.