Collection: Jasper arrow head

Mineral class- Silicate (specifically a Tectosilicate)
Chemical compound- Silicon dioxide,identical to quartz,but heavily impure and opaque due to 20% or more foreign inclusions.
Crystal system- Trigonal it features a microcrystalline or cryptocrystalline structure,meaning its individual quartz crystals are microscopic and packed closely together rather then forming large visible crystal face.
Hardness- 6.5-7 on the MOHs scale
Rock formation-
Sedimentary process: Silica rich groundwater seeps into soft sediment layers like clay,sand or volcanic ash and slowly evaporates or changes ph ,leaving behind microscopic silica that acts as a natural cement to lock the particles together.
Volcanic environment:
Hot silica bearing fluids can fill and crystallize inside fractures,cavities or voids within existing igneous rock.
Impurities and colours: The diverse colours of jasper come from specific trapped elements: Hematite or iron creates red,goethite creates yellow and brown and chlorite creates green.