Tavorite
Chemical formula: LiFe<sup>3+</sup>PO<sub>4</sub>(OH)
A rare lithium iron phosphate, forming greenish-yellow, granular aggregates in granitic pegmatites.
Properties
- Mohs hardness
- 5
- Luster
- Vitreous to Resinous
- Streak
- Pale yellow
- Density
- 3.29-3.35
- Cleavage
- Good on {010}
- Fracture
- Uneven to Sub-Conchoidal
- Transparency
- Translucent to Opaque
- Crystal system
- Triclinic
Diagnostic features
## Identification Key diagnostic features of tavorite include its characteristic yellowish-green or olive color, vitreous to resinous luster, and its occurrence environment—alteration zones in phosphate-rich granitic pegmatites. It often forms granular masses in association with primary phosphates. ## Distinguishing from Similar Minerals Tavorite can be confused with other secondary phosphates of similar color, such as cyrilovite, rockbridgeite, or members of the amblygonite group. It is the iron (Fe³⁺) analog of montebrasite. Definitive differentiation from these minerals often requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis. ## Crystal Forms Tavorite crystallizes in the triclinic system. Well-formed crystals are extremely rare and usually very small. It is most commonly found as granular aggregates, compact masses, or radial aggregates forming crusts.
Geological environment
## Genesis Tavorite is a secondary mineral. It forms as a result of hydrothermal alteration or weathering of primary lithium, iron, and manganese phosphates, primarily from the triphylite-lithiophilite series. Its occurrence is restricted to weathering zones in complex, phosphate-rich granitic pegmatites. ## Mineral Associations This mineral often co-occurs with other phosphates. Its most common associated minerals include: triphylite, lithiophilite, barbosalite, rockbridgeite, strengite, cyrilovite, as well as members of the amblygonite-montebrasite group, quartz, and muscovite. ## Localities The most important and also the type locality for tavorite is the Sapucaia mine in Sapucaia do Norte (Minas Gerais, Brazil). Significant specimens also come from pegmatites in Custer and Pennington counties in South Dakota (USA), as well as from New Hampshire (USA). Additionally, its occurrence has been reported in Rwanda, Spain, and Portugal.
Rarity
Rare
For collectors
## Quality Criteria The collector's appeal of tavorite primarily depends on the intensity and purity of its greenish-yellow color. Specimens in the form of rich crusts or large granular masses are more highly valued. The most sought-after are rare, well-formed microcrystals. Association with other rare phosphates, forming aesthetic compositions, also adds significant value. ## Popular Localities The type locality, the Sapucaia mine in Brazil, is considered classic and provides the best specimens. Specimens from there serve as a reference point for this mineral. Samples from pegmatites in the Black Hills region of South Dakota, USA, are also sought after.
Care and storage
## Cleaning Tavorite specimens should be cleaned very carefully, using a soft brush to remove dust. If necessary, they can be rinsed with distilled water. Ultrasonic cleaners should be avoided, as they can damage fragile aggregates or detach them from the host rock. ## What to Avoid As a phosphate, this mineral can be sensitive to strong acids. Contact with chemicals and detergents should be avoided. Although there is no evidence of fading, it is advisable to avoid prolonged exposure to direct sunlight. It should also be protected from sudden temperature changes. ## Storage It is recommended to store specimens in closed collector boxes or display cases to protect them from dust and mechanical damage. Since it often occurs with other, more fragile minerals, it should be handled gently.