Quartz Vein in Basalt or Slate
Quartz-veined Metamorphic/Igneous Rock · Mineral Specimen
Crystal System
Trigonal (Quartz vein), Massive habit, water-worn pebble shape
Mineral Group
Silicates - Tectosilicates
Chemical Formula
SiO2 (Quartz vein) with various silicate minerals in host rock
Formation Process
Hydrothermal vein filling where silica-rich fluids precipitated quartz into a fracture within a pre-existing host rock, later subjected to weathering and water-transport
About This Crystal
A water-worn dark grey to black pebble or cobble featuring a prominent, contrasting white quartz band or vein running diagonally across its surface, showing smooth rounded contours from fluvial transport
Physical Characteristics
Dark grey host rock with white quartz band, white streak for quartz, no distinct cleavage in massive quartz, conchoidal fracture in quartz, specific gravity around 2.65 for quartz portion
Optical Properties
Quartz is uniaxial positive with a refractive index of 1.544-1.553, doubly refractive, vitreous luster on the quartz portion
Hardness & Durability
Origin Region
Found worldwide, typically in areas with ancient volcanic or tectonic activity, riverbeds, or glacial drift
Hardness & Durability
Mohs hardness of 7 for the quartz vein, host rock hardness varies (likely lower if limestone or slate, higher if basalt); very durable for general handling
Care & Maintenance
Wash with warm soapy water and a soft brush, store away from softer stones that could be scratched by the quartz portion
Rarity & Value
Very common geological formation, little commercial value as a gemstone but interesting as a standard geological specimen or garden stone
Special Characteristics
Features a distinct hydrothermal vein intrusion preserved inside a host rock pebble, demonstrating geological faulting and mineral infill
Lore & History
Often used in crystal grids or as grounding stones in metaphysical practices due to the combination of amplifying quartz and stabilizing dark host rock, though this represents traditional folklore rather than scientific claims