Poldervaartite xls; N'Chwaning II Mine, Kalahari Manganese Field, South Africa; Min; unique piece
Poldervaartite crystals from the N'Chwaning II Mine, Kalahari Manganese Field, South Africa – miniature specimen as unique piece
This miniature specimen with Poldervaartite crystals from 2002 from the N'Chwaning II Mine, Kalahari Manganese Field, South Africa shows an attractive development of this rare calcium manganese silicate mineral. A rounded, yellowish to cream colored crystal aggregate of densely intergrown Poldervaartite crystals sits prominently on the dark matrix.
The crystals form a compact, spherical aggregate with a finely textured surface. The strong color contrast between the pale crystal aggregate and the dark matrix gives the specimen a particularly aesthetic appearance. Poldervaartite is one of the characteristic but comparatively rarely offered mineral species from the N'Chwaning mines, making well developed pieces like this especially interesting for collectors.
Geology & Origin
The N'Chwaning II Mine in the Kalahari Manganese Field is one of the most important localities worldwide for rare manganese minerals. The deposits formed in manganese rich sedimentary rocks that were later modified by metamorphic and hydrothermal processes. Within this complex geochemical environment numerous rare silicates, oxides and other manganese minerals developed. Poldervaartite typically occurs there as yellowish to cream colored aggregates and is closely associated with the diverse mineral paragenesis of the Kalahari Manganese Field.
This table is for general information and orientation, although the sizes of the stones may vary. In addition, this specification is handled differently from region to region.
| Sizes | Description | approx. Sizes in mm/cm | approx. Sizes in INCH | |
| Capsule | Capsule | 0.1–0.5 mm in a transparent hard capsule (approx. 1 cm) | capsule contents 0.1–0.5 mm | capsule contents 0.004–0.02 in |
| TN/mm | Micromount (TN = Thumbnail) | everything fitting in a TN Perky box or a MM box of approx. 1 in | approx. 0.5–2.5 cm | max. 1 in |
| Min | Miniature specimen | will not fit a TN or MM box anymore | approx. 2.5–5 cm | approx. 0.2–1.0 in |
| Scab | small cabinet specimen | approx. one-third to half a hand size | approx. 5–9 cm | approx. 1.0–2.0 in |
| Cab | cabinet specimen | full hand size | approx. 9–15 cm | approx. 2.0–3.5 in |
| large Cab | large cabinet specimen | approx. two hand sizes | approx. 15–30 cm | approx. 3.5–6.0 in |
| very large Cab | very large cabinet specimen | everything larger, no upper limit |
Abbreviations commonly used in mineralogy.
| Abbreviation | Meaning |
| xl | single crystal, possible with matrix |
| xls | noticeable crystals |
| (xl) | embedded or damaged |
| (xls) | embedded or damaged |
| MASS | massive and/or amorphous pieces |
| TYP | type locality of the original description |
| SWUV | shortwave-UV-reaction |
| UV | ultraviolet reaction |
| SC | self-collected |
| U | unique (single unique piece) |
Usage Instructions
This product is ideal as a collector's item, decorative element, teaching material, or for scientific and exhibition purposes.
Legal Notices
Safety
We accept no liability for damages resulting from improper and/or non-recommended use. Please carefully assess the suitability of the product before any alternative use.
Responsible Provider
Mikon Mineralienkontor GmbH
Steinslieth 11
D-37130 Gleichen OT Klein Lengden
Email: info@mikon-online.com
| shipment-weight, NOT netto weight (kg) | 0.080000 |
|---|