Tantalowodginite
Chemical formula: (Mn²⁺,◻)Ta⁵⁺Ta⁵⁺₂O₈
Tantalowodginite is a rare mineral from the wodginite group, an oxide of tantalum and manganese, found in granitic pegmatites.
Properties
- Mohs hardness
- 5-5.5
- Color
- Orange-red to deep red
- Luster
- Adamantine
- Streak
- Yellowish-tan
- Density
- 7.61
- Cleavage
- on {100}
- Fracture
- Conchoidal
- Transparency
- Opaque
- Crystal system
- Monoclinic
Diagnostic features
## Identification Characteristic features of tantalowodginite include its black color, strong metallic or submetallic luster, high density (the specimen is very heavy for its size), and high hardness. It occurs in association with other tantalum minerals in pegmatites. ## Distinguishing from Similar Minerals It can be confused with other black, heavy pegmatite minerals such as columbite, tantalite, wodginite, or tapiolite. Definitive differentiation from these minerals, especially from wodginite and tantalite-(Mn), requires advanced chemical analyses (e.g., EDS) and crystallographic analyses (e.g., XRD) to determine the exact composition and structure. ## Crystal Forms Tantalowodginite crystals are usually poorly developed, with a tabular or short prismatic habit. They often form granular aggregates or irregular masses embedded in the host rock (quartz, albite).
Geological environment
## Genesis Tantalowodginite is a mineral of magmatic origin, crystallizing in the late stages of the evolution of granitic pegmatites, especially those of the LCT (lithium-cesium-tantalum) type, which are extremely enriched in rare elements such as tantalum. ## Mineral Associations It co-occurs with other minerals typical of tantalum-bearing pegmatites, such as albite, quartz, microcline, muscovite, as well as with other tantalum and niobium minerals, e.g., wodginite, tantalite-(Mn), and microlite. ## Localities The only confirmed and described locality (type locality) of this mineral in the world is the Tanco pegmatite, located on Bernic Lake in Manitoba, Canada. This is one of the most mineralogically diverse pegmatite deposits in the world.
Rarity
Extremely rare
For collectors
## Quality Criteria For collectors, the most important criterion is the degree of crystal development – specimens with visible, even if small, crystal faces are much more valuable than amorphous grains. The size of the specimen and its association with other minerals, e.g., contrasting white albite, are also important. Purity is not a key criterion, as the mineral is opaque. ## Popular Localities The only source of tantalowodginite specimens is the Tanco mine in Canada. Material from this locality is extremely rare on the collector's market and commands very high prices, being within reach only of the most advanced collectors specializing in systematics or rare pegmatite minerals.
Care and storage
## Cleaning Tantalowodginite specimens should be cleaned very carefully, using a soft brush to remove dust. If necessary, distilled water can be used, but prolonged soaking should be avoided. Ultrasonic cleaners are not recommended. ## What to Avoid Contact with strong acids and other chemicals that could damage the mineral's surface should be avoided. Despite its high hardness, it is brittle, so it should be protected from impacts and falls. ## Storage Tantalowodginite specimens are best stored in separate, padded display boxes to prevent scratching by other minerals and to protect them from mechanical damage. It is not sensitive to sunlight, but stable conditions are always recommended.