Despite the fact that prisms of chamids show no evidence of ultrastructure, with fractures appearing conchoidal
rather than revealing nanometric units or folios, there is an interesting similarity in their overall interdigitating form with ultrastructure reported for some of the pterioid prisms.
These findings challenge previous ideas about the minimum level of cognitive and morphological complexity required to produce numerous conchoidal
flakes," he said.
Por outro lado, o arenito silicificado de fratura conchoidal
se encontra disponivel de maneira local dentro dos intersticios dos derramamentos basalticos por toda a provincia de Misiones (Remesal e Chavez 2014), inclusive na area da cidade de Corpus (INSUGEO 2007).
Silcrete may be distinguished from other siliceous rocks by its lustrous conchoidal
fracture; it is so strongly cemented that it fractures evenly through grains and matrix, whereas many quartzites fracture around the grains.
SEM images indicate a high degree of conchoidal
fracturing, possible triple point morphology typical of tripoli, and particle sizes ranging from 10-30 microns.
The best quality were deemed to be of French or English origin, translucent with a smooth surface of a "uniform tint of light yellow or brown color, and slightly conchoidal
There is no discernible cleavage, and the fracture is conchoidal
. Norilsk sperrylite crystals are brittle and many have microfractures visible along the crystal faces.
Methods typically employed by igneous petrologists and gemologists to identify glass include the observance of conchoidal
fracture, determination of hardness, reaction to a hotpoint, microscopy, and spectroscopy (Gemological Institute of America [GIA] 1996; GIA 1998; Hatch et al.
Along with the carbon, broken and irregular fragments of glass shards exhibiting uneven to conchoidal
fractures have been noticed in the limestone samples (Fig.
1) contained zircons with varying morphologies, including colorless to brown anhedral fragments with conchoidal
fractures and colorless to light brown prisms with aspect ratios of 2.5-5 (Table 2, Figs.
Medium hard, very pale brown fabric (5YR 7/6) with hackly to conchoidal
break, reddish yellow (5YR 7/6) flashes outside; abundant, medium, white to orange, glassy, subrounded to rounded, tabular to spherical inclusions.
10YR4/4 moist: apedal with conchoidal
partings around weathered-stone cores (10Y4/1); weathered basalt rock fragments more common with depth; giving way to basalt at depth (obscured but evident on north face of cutting); field pH 7 Location: Mackenzie's Waterholes Creek; north side of railway cutting Site: Gently convex, broad flat spur with local relief <20 m Classification of the silty mantle: Red Podzolic (Stacc et al.