Jasper
Silicon Dioxide (Microcrystalline Quartz) var. Jasper · Semi-Precious Gemstone / Lapidary Material
Crystal System
Trigonal (Hexagonal system) but occurs as a microcrystalline / cryptocrystalline mass. Habit is typically massive, as seen in this rough, river-worn specimen.
Mineral Group
Silicates; Tectosilicate (Quartz group)
Chemical Formula
SiO2 (Silicon Dioxide) primarily, with significant impurities such as Fe2O3 (Iron Oxide) that provide the brown and yellow pigmentation.
Formation Process
Sedimentary or Hydrothermal; forms when silica-rich fluids permeate porous rock or sediment, depositing microcrystalline quartz that incorporates local minerals and oxides.
About This Crystal
This is a rough, opaque specimen showing a waxy to dull luster. The color is variegated with earth tones including ochre yellow, deep chocolate brown, and reddish-tan. The surface is weathered and shows several percussion marks and cracks typical of river-transported stones. It lacks visible crystalline faces due to its massive, cryptocrystalline nature.
Physical Characteristics
Color: Brown and yellow; Streak: White; Cleavage: None; Fracture: Conchoidal to uneven; Specific Gravity: 2.58–2.91; Fluorescence: Typically inert.
Optical Properties
Refractive Index: 1.544–1.553; Opaque (light does not pass through even thin edges); No pleochroism or dispersion visible in hand specimen.
Hardness & Durability
Origin Region
Globally distributed; notable sources include India, Brazil, Madagascar, and the United States (Western states). Often found in alluvial deposits or as nodules in volcanic rock.
Hardness & Durability
Mohs Hardness: 6.5–7; Toughness: Excellent (no cleavage makes it very resistant to breaking); High durability for jewelry and carvings.
Care & Maintenance
Safe to clean with warm soapy water and soft brushes. Jasper is stable and not sensitive to light, but should be kept away from harsh chemicals like hydrofluoric acid. Ultrasonic cleaners are generally safe.
Rarity & Value
Common; value is determined primarily by unique patterns (scenic, orbicular) or color saturation. Rough material of this type is inexpensive, often sold by weight.
Special Characteristics
Microcrystalline structure prevents light penetration. The color zoning in this piece is caused by varying concentrations of iron oxides during the mineral's deposition.
Lore & History
Historically known as the 'Supreme Nurturer' in traditional lore. Used by ancient civilizations for seals, talismans, and jewelry. It was mentioned in the Bible as one of the stones in the breastplate of the High Priest and is traditionally associated with grounding and stability.