Wakefieldite-(Nd)

Chemical formula: NdV⁵⁺O₄

Wakefieldite-(Nd) is a rare neodymium vanadate with tetragonal crystals, named after Canadian mineralogist John Wakefield.

## Characteristics Wakefieldite-(Nd) is a mineral belonging to the xenotime group, being a neodymium vanadate. It forms very small, dipyramidal crystals with a tetragonal structure, reaching sizes up to several tens of micrometers. It occurs as single crystals or small aggregates. Due to its microscopic size, its visual features are difficult to observe without specialized equipment. In thin sections under a microscope, it is colorless or exhibits a delicate, pinkish tint. ## Physical Properties This mineral is characterized by high hardness, estimated at 4-5 on the Mohs scale. Its luster is described as vitreous to subadamantine. It is transparent, which can be observed in thin microscopic preparations. The density of wakefieldite-(Nd) is high, approximately 5.23 g/cm³. ## History and Name Wakefieldite-(Nd) was first described in 1989 by Kotaro Kato and Yasushi Saka. The mineral is named in honor of John S. Wakefield (b. 1929), a Canadian mineral collector and photomicrographer, who first identified a related mineral, wakefieldite-(Y). The "(Nd)" suffix in the name indicates the dominance of neodymium as the rare earth element in its chemical composition. The type locality where it was discovered is the Arase mine in Kōchi Prefecture, Japan.

Properties

Mohs hardness: 4-5
Luster: Vitreous to subadamantine
Streak: White
Density: 5.23
Cleavage: Good on {101}
Fracture: Uneven
Transparency: Transparent
Crystal system: Tetragonal

Diagnostic features

## Identification Identification of wakefieldite-(Nd) is impossible without advanced analytical techniques. It requires the use of a scanning electron microscope (SEM) with chemical composition analysis (EDS) to confirm the presence of neodymium and vanadium. The characteristic tetragonal, dipyramidal form of microcrystals is also distinctive. ## Distinguishing from Similar Minerals It can be confused with other minerals from the xenotime group, such as wakefieldite-(Y), wakefieldite-(Ce), or xenotime-(Y). Differentiation is only possible based on chemical analysis, which will show which rare earth element dominates the mineral's structure. ## Crystal Forms It forms simple, pyramidal (dipyramidal) crystals with a square cross-section, typical of the tetragonal system. The crystals are microscopic in size and usually occur as single, well-formed individuals on the surface of other minerals.

Geological environment

## Genesis Wakefieldite-(Nd) forms under low-temperature hydrothermal conditions. At the type locality (Arase mine), it was found in fractures of siliceous rocks (cherts) of sedimentary origin that underwent subsequent hydrothermal processes. ## Mineral Associations This mineral coexists with quartz, hematite, hausmannite, braunite, and other minerals from the xenotime group, such as wakefieldite-(Y). ## Localities The confirmed occurrence of wakefieldite-(Nd) is extremely limited. The most important and type locality is the Arase mine in Kami City, Kōchi Prefecture, on Shikoku Island, Japan. Beyond this locality, its presence has been reported in a few other places worldwide, including the Carlin Gold mine in Nevada (USA), but specimens from Japan remain the reference material.

Rarity

Very rare

For collectors

## Quality Criteria As a microscopic mineral, wakefieldite-(Nd) is not evaluated according to typical criteria such as color or clarity visible to the naked eye. The most highly prized specimens are those with well-formed, sharp, and undamaged microcrystals that stand out clearly from the host rock. The abundance of crystals on the matrix and confirmed chemical analysis significantly increase the collectible and scientific value of the specimen. ## Popular Localities The only source of collectible specimens is the type locality – the Arase mine in Japan. Specimens from this location are highly sought after by collectors specializing in micromounts and rare earth element minerals.

Care and storage

## Cleaning Due to the extremely small size of the crystals and their rarity, mechanical cleaning is neither recommended nor practiced. Specimens are usually left in their natural state on the host rock. ## What to Avoid Avoid contact with strong acids, which can damage the mineral. There is no detailed data on sensitivity to light or temperature, but standard caution is recommended, as with other rare minerals. ## Storage Microscopic specimens should be stored in specialized "micromount" boxes, which protect them from dust, moisture, and mechanical damage. Display is only possible under a microscope.