Aspedamite

Chemical formula: &#₉₇₄₄;₁₂(Fe₃+,Fe₂+)₃Nb₅+₄[Th₄+(Nb₅+,Fe₃+)₁₂O₄₂][(H₂O),(OH)]₁₂

Aspedamite is a very rare mineral from the crichtonite group, found in Norway as small, black, metallic crystals.

## Characteristics Aspedamite is an extremely rare mineral belonging to the crichtonite group. It occurs as small, tabular or hexagonal crystals, reaching up to 1 mm in size. Its color is black, and on thin edges, it can be translucent reddish-brown. It is an opaque mineral. ## Physical Properties Aspedamite crystals exhibit a metallic luster. Its Mohs hardness is estimated at 6, and its density is approximately 4.73 g/cm³. This mineral does not show cleavage, and its fracture is conchoidal. ## History and Name Aspedamite was first described in 2011 by Gunnar Raade and his colleagues. Its name comes from its type locality – the Aspedammen syenite pegmatite in the municipality of Porsgrunn (formerly Tvedalen) in Norway. It was approved by the International Mineralogical Association (IMA) under number 2010-002.

Properties

Mohs hardness: 6
Luster: Metallic
Streak: Red-brown
Density: 4.73
Cleavage: None
Fracture: Conchoidal
Transparency: Opaque, Translucent in thin splinters
Crystal system: Trigonal

Diagnostic features

## Identification Amateur identification of aspedamite is practically impossible. It requires advanced analytical techniques, such as X-ray microanalysis (EDS/WDS) and X-ray diffraction (XRD), to confirm its complex chemical composition and crystal structure. Visual features, such as black color, metallic luster, and hexagonal crystal outline, are merely indicative. ## Distinguishing from similar minerals Aspedamite is visually indistinguishable from other black, metallic minerals of the crichtonite group, such as crichtonite, senaite, or davidite. Definitive differentiation is possible only through chemical analysis. ## Crystal forms It forms small, hexagonal, tabular crystals, often with poorly developed faces. They usually occur as single, isolated crystals embedded in the host rock.

Geological environment

## Genesis Aspedamite forms in syenite pegmatites. It is a mineral of magmatic origin, crystallizing in the late stages of pegmatite formation from residual, rare-element-rich fluids. ## Mineral associations This mineral co-occurs with other rare pegmatite minerals. At the type locality, it was found in association with aegirine, albite, ankylite-(Ce), catapleiite, eudialyte, mosandrite-(Ce), and wöhlerite. ## Localities The only confirmed occurrence of aspedamite in the world is its type locality: the Aspedammen syenite pegmatite quarry, in the Vestfold region, Norway.

Rarity

Extremely rare

For collectors

## Quality criteria As a "micromount" type mineral, of purely scientific and systematic value, the main quality criteria are the degree of crystal development and size, as well as its analytically confirmed identity. The most valuable specimens are those with distinct, undamaged crystals, well-seated on a contrasting rock matrix. ## Popular localities The only source of specimens is the Aspedammen quarry in Norway. Material from this locality is extremely difficult to obtain and appears on the collector's market sporadically, mainly among specialized rare mineral collectors.

Care and storage

## Cleaning Due to its extreme rarity and small crystal sizes, mechanical cleaning is not recommended. If absolutely necessary, compressed air can be used to remove loose dust particles. Avoid contact with water and chemicals. ## What to avoid Avoid all chemicals, acids, detergents, and ultrasonic cleaners. The crystals are brittle and susceptible to mechanical damage. Store away from moisture and extreme temperatures. ## Storage Aspedamite specimens, due to their small size and scientific value, should be stored in specialized "micromount" boxes or sealed containers, protecting them from dust, moisture, and physical damage.

External references

https://en.wikipedia.org/wiki/https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FAspedamite