Tangerine Quartz (Iron-coated Quartz)
Quartz with Hematite/Limonite coatings · Mineral Specimen / Semi-Precious Gemstone
Crystal System
Trigonal; typically occurs as elongated hexagonal prisms terminating in rhombohedral faces. This specimen shows a tapered, singly-terminated prismatic habit.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 with surface Fe2O3 (Hematite) or FeO(OH)·nH2O (Limonite)
Formation Process
Hydrothermal formation where silica-rich fluids crystallize in cavities; the orange color is a secondary formation process where iron-rich water deposits hematite or limonite onto the surface of the quartz.
About This Crystal
Elongated prismatic crystal with a transparent to translucent body. It features a distinct orange to brownish-orange surface coating. Luster is vitreous (glass-like) on faces and greasy on fractured surfaces. Internal clarity is visible through the surface oxidation.
Physical Characteristics
Color: Pale orange to rusty brown; Streak: White; Cleavage: None; Fracture: Conchoidal to uneven; Specific Gravity: 2.65; Fluorescence: Usually inert/none; Tenacity: Brittle.
Optical Properties
Uniaxial positive; Refractive Index: 1.544–1.553; Birefringence: 0.009; No pleochroism; Exhibits typical quartz transparency obscured by surface inclusions.
Hardness & Durability
Origin Region
Notable sources include Brazil (Minas Gerais), Madagascar, and the United States. It typically forms in hydrothermal veins or geodes.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good, though the surface coating can be scratched or abraded by harder materials; Stability: Generally stable but sensitive to hydrofluoric acid.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid harsh chemicals or acidic cleaners as they may strip the orange iron coating. Store separately from harder gemstones like Topaz or Sapphire.
Rarity & Value
Common; Value is determined by crystal integrity, termination quality, and the vibrancy of the orange coating. Specimens with intact points and deep color are more desirable.
Special Characteristics
Features a natural iron-oxide 'skin' or coating. May show 'phantom' layers if the iron was trapped under a later layer of clear quartz growth.
Lore & History
Historically, quartz has been used for tool-making and ritual objects across all continents. In metaphysical traditions, Tangerine Quartz is associated with the Sacral Chakra and is believed to promote creativity, sexuality, and playful energy.