Flint
Quartz var. Flint · Mineral Specimen / Sedimentary Stone
Crystal System
Trigonal (Microcrystalline / Cryptocrystalline Quartz)
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2
Formation Process
Sedimentary, forming as chemical precipitates or replacement deposits of silica within chalk or limestone formations during diagenesis.
About This Crystal
The specimen is an irregularly shaped nodule with a smooth, conchoidal fracture surface displaying characteristic dark gray to black interior zones surrounded by lighter white to yellowish-brown weathered cortex layers.
Physical Characteristics
Opaque to translucent at thin edges, vitreous to waxy luster, white streak, hardness of 7 on the Mohs scale, conchoidal fracture with no true cleavage, and specific gravity of approximately 2.60 to 2.65.
Optical Properties
Microcrystalline aggregates exhibit aggregate double refraction with a low birefringence typical of quartz, though individual micro-crystals are too small to resolve optically.
Hardness & Durability
Origin Region
Worldwide, commonly found in chalk or marly limestone formations in Europe, North America, and Asia.
Hardness & Durability
Mohs hardness of 7. Highly durable, brittle with sharp conchoidal edges, excellent resistance to weathering and chemicals.
Care & Maintenance
Can be washed safely with warm soapy water. Requires no special storage precautions beyond avoiding severe impacts that could chip the sharp edges.
Rarity & Value
Common, widely distributed globally. Value is low to moderate, largely determined by historical significance, size, and whether fashioned into tools or interesting mineral specimens.
Special Characteristics
Historically famous for producing sparks when struck against steel due to its hardness and microcrystalline structure, widely used in prehistoric stone tool making.
Lore & History
Flint holds immense historical significance as one of the primary materials used by early humans for fashioning stone tools, weapons, and fire-starting kits during the Stone Age. In modern crystal lore, it is often associated with grounding energy, cutting through mental blocks, and protection.