Embedded Alumohydrocalcite crystals from Thornbury, Bristol, UK – micromount as unique piece.
This micromount shows embedded cream-white Alumohydrocalcite crystals in a dark matrix. The crystals are only clearly visible under magnification but exhibit fine radial structures and stand out well against the host rock. Occasional orange accessory minerals add contrast to the surface.
Alumohydrocalcite is a rare carbonate mineral typically found in secondary formation zones of bauxite or limestone deposits. Specimens from the UK are rarely documented and of particular interest for systematic collections.
Geology & origin:
Thornbury near Bristol is located in an area with a complex geological structure, known for clay and limestone deposits. Mineral formation there often occurs through sulfate- and carbonate-rich solutions. The locality yields only very rare microscopic but systematically important minerals like this embedded Alumohydrocalcite.
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
