Limonite with Quartz
Goethite/Lepidocrocite (var. Limonite) with Quartz · Mineral Specimen
Crystal System
Amorphous (Limonite) and Trigonal (Quartz); Habit is massive, earthy, and microcrystalline
Mineral Group
Oxides / Hydroxides and Tectosilicates
Chemical Formula
FeO(OH)·nH2O + SiO2
Formation Process
Secondary formation through the weathering of iron-bearing minerals (limonite) and hydrothermal deposition (quartz)
About This Crystal
The specimen exhibits a rugged, earthy texture dominated by rusty-yellow and brownish-red iron oxides (limonite). Small, translucent to vitreous patches of microcrystalline quartz are visible throughout, creating a grainy surface texture. The luster varies from dull/earthy in the oxides to vitreous on the quartz surfaces.
Physical Characteristics
Color: Yellow-brown to reddish-brown with grayish clear patches; Streak: Yellowish-brown; Cleavage: None visible (massive); Fracture: Uneven to conchoidal (in quartz sections); Specific Gravity: 2.7 - 4.3; Fluorescence: Usually inert.
Optical Properties
Sub-vitreous to dull; Quartz components are refractive (n=1.544-1.553), while the limonite remains opaque to translucent on thin edges with high relief.
Hardness & Durability
Origin Region
Worldwide; commonly found in iron-rich oxidation zones (e.g., Brazil, USA, Germany)
Hardness & Durability
Variable; Limonite is roughly 4-5.5 on Mohs scale, while Quartz is 7. Overall durability is moderate but prone to crumbling if heavily weathered.
Care & Maintenance
Keep dry to prevent further oxidation or softening of the matrix. Clean with a soft brush and warm soapy water; avoid harsh chemicals or acidic cleaners which may dissolve the iron oxides.
Rarity & Value
Common; Value is generally low, primarily of interest to mineral collectors or as a lapidary rough (if solid enough).
Special Characteristics
Displays a 'gossan' appearance typical of the oxidized cap of an ore deposit; features micro-druzy quartz coatings on iron-rich matrix.
Lore & History
Historically used as an iron ore and as a natural pigment (ochre) for cave paintings. In traditional lore, it is considered a grounding stone associated with the Root Chakra and physical endurance.