20999-59 - NWA Possible Achondrite Meteorite Porphyritic Basalt. In study. 192 g Invertebrates Alethopteridae

Alethopteridae

-Globidens phosphaticus (Bardet et al

Whittakerites

and clusters of refractory materials that often form during the discharge phase of lightning strikes propagating into silica-rich quartzose sand

Beautiful plaque containing the remains of many stems of this species of moroccan crinoid (Scyphocrinites)

20999-59 - NWA Possible Achondrite Meteorite Porphyritic Basalt. In study. 192 g Invertebrates AlethopteridaePetrographic description Under petrographic microscope, the sample is a fine grained volcanic rock with olivine and pyroxene phenocrysts, surrounded by a fine grained matrix (Figs. 2 and 3). Phenocrysts show deformation, developing twins and cracks. Olivine grains have a thin rim (Figs. 2 and 3) of iddingsite (reddish border). Pyroxene is pale brown and presents some plagioclase inclusions. The matrix is formed by tabular euhedral plagioclase and