31 October (Angola ) within release Geology, mineralogy, paleontology goes into circulation Stamp Mineral: Barite face value 5 Angolan escudo
Stamp Mineral: Barite in catalogues | |
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Michel: | Mi:AO 572 |
Stamp is square format.
Also in the issue Geology, mineralogy, paleontology:
Stamp Mineral: Barite it reflects the thematic directions:
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form