Record details

    "Cave pearls" as a by-product of building constructions
    Buřival, Zbyněk
    Faimon, Jiří
    Schwarzová, Monika
    Štelcl, Jindřich
    Vávra, Václav
Publication type
    článek v periodiku
Source title - serial
    Slovenský kras (Acta Carsologica Slovaca)
    Roč. 46, č. 1
Thesaurus term
    dripwater pool
    percolating water
    rock fragment
Abstract (in english)
   Cave pearls are frequently found in disused adit leading bellow the Špilberk Hill in Brno (Czech Republic). Each pearl consists of (1) a core comprised of an extraneous rock fragment and (2) a body organized into light and dark calcite layers. The number of the main layers roughly corresponds to 30 years of the total adit age. The darker layers occasionally show a sub-structure consisting of 2-3 extremely fine layers of various gray tones. Dendrite-like structures were observed in some cases. Conditions, necessary for pearl formation, were recognized as follows: (1) percolating waters supersaturated with respect to calcite, (2) free rock fragments as a basis for calcite nucleation, and (3) turbulent water circulation in dripwater pools preventing the fragments to fix at pool bottom during calcite growth. Initial bigger irregular rock fragments (10-15 mm in diameter) lead to formation of pearls of irregular shape. Tiny fragments (1-3 mm in diameter) lead to near spherical pearls.
    MU Brno, Přírodovědecká fakulta
Contributor code
    MU, PřF
Source format
Import date
    8. 8. 2012