ISSN
print 2570-7337
online 2570-7345
Occurrence of Al-Fe phosphates in conglomerates at Kamenný Újezd near Rokycany (Czech Republic)
Keywords
Abstract
An interesting occurrence of secondary phosphates fluorwavellite, variscite and strengite in the Barrandian area has been newly discovered in Kamenný Újezd near Rokycany (Czech Republic). Phosphates crystallize on cracks of hornfels pebbles in weathered conglomerates and in cavities of quartz veins that penetrate them. Fluorwavellite forms white, needle-like, radially rayed aggregates with a diameter of up to 3 cm on the cracks and white to slightly yellowish spherical aggregates up to 1 cm in size in cavities. Variscite occurs in fissures in the form of flat radial aggregates of white colour and pearly lustre up to 0.8 mm in size. In the cavities of quartz veins, variscite forms spherical aggregates up to 0.8 mm in diameter and reniform layers of white, light beige, light gray, and light pink colours. Variscite is covered with a layer of strengite approximately 0.06 to 0.08 mm thick. The WDS quantitative analyses, X-ray powder patterns, and refined unit cell parameters are given for all described mineral phases.
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References
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