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conchoidal fractures

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SEM images of sea-glass surface textures. A) Conchoidal fractures (CF) on a relatively fresh grain with subrounded edges. B) Crescentic gouge (CG) on a frosted grain. C) Straight groove (SG) and c-shaped cracks (C) on a rounded, frosted grain. D) Halite (H) precipitation on a subrounded grain. E) Solution pits (P) on a rounded, frosted grain. F) C-shaped cracks (C) formed by chemical weathering on a rounded, frosted grain. G) Diatoms (D) and silica precipitation (SP) within a crack on a non-frosted grain. H) Vermiculate texture (V) resembling borings on a non-frosted grain.

SEM images of sea-glass surface textures. A) Conchoidal fractures (CF) on...

Published: 01 October 2010
Figure 5 SEM images of sea-glass surface textures. A) Conchoidal fractures (CF) on a relatively fresh grain with subrounded edges. B) Crescentic gouge (CG) on a frosted grain. C) Straight groove (SG) and c-shaped cracks (C) on a rounded, frosted grain. D) Halite (H) precipitation
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Hand specimen, Haigh Cannel, Lancashire, note the conchoidal fracture. A carved door knob is used for scale. Photograph, A. A. France.

Hand specimen, Haigh Cannel, Lancashire, note the conchoidal fracture. A ca...

Published: 03 November 2022
Fig. 3. Hand specimen, Haigh Cannel, Lancashire, note the conchoidal fracture. A carved door knob is used for scale. Photograph, A. A. France.
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Carducciite, black prismatic crystals up to 0.5 mm. The conchoidal fracture of carducciite is clearly visible.

Carducciite, black prismatic crystals up to 0.5 mm. The conchoidal fracture...

Published: 01 December 2014
F ig . 1. Carducciite, black prismatic crystals up to 0.5 mm. The conchoidal fracture of carducciite is clearly visible.
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Angle-resolved X-ray photoelectron spectra of a conchoidally fractured pyrite surface approximately normal to (001). Take-off angle is minimum for the top spectrum and is maximum for the spectrum plotted at the bottom of the stack.

Angle-resolved X-ray photoelectron spectra of a conchoidally fractured pyri...

Published: 01 February 2004
F igure 1. Angle-resolved X-ray photoelectron spectra of a conchoidally fractured pyrite surface approximately normal to (001). Take-off angle is minimum for the top spectrum and is maximum for the spectrum plotted at the bottom of the stack.
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—Typical lithologic appearance of Valmont dolomite. Conchoidal fracture and even bedding are diagnostic of Valmont dolomite (NE. 14, NW. 14, Sec. 7, T. 17 S., R. 11 E.).

—Typical lithologic appearance of Valmont dolomite. Conchoidal fracture and...

Published: 01 August 1953
Fig. 8. —Typical lithologic appearance of Valmont dolomite. Conchoidal fracture and even bedding are diagnostic of Valmont dolomite (NE. 1 4 , NW. 1 4 , Sec. 7 , T. 17 S., R. 11 E.).
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SEM photomicrographs illustrating typical features and textures on Fish Lake (old and young) and Snake Creek samples. (a) relict polished surface (pws) with deep arcuate grooves, (b) close-up of deep arcuate groove containing crushing features (box in a), (c) quartz crystal showing fracture faces (ff) and subparallel crushing features (spcf), and (d) another quartz crystal exhibiting fracture faces, subparallel crushing features, and conchoidal crushing features (ccf), (e) subparallel conchoidal fractures, conchoidal fractures, and crushing features, (f) close-up of conchoidal fractures and crushing features (box in e), (g) conchoidal fractures and subparallel crushing features, and (h) fracture faces with subparallel conchoidal fractures and conchoidal crushing features.

SEM photomicrographs illustrating typical features and textures on Fish Lak...

Published: 27 September 2004
showing fracture faces (ff) and subparallel crushing features (spcf), and ( d ) another quartz crystal exhibiting fracture faces, subparallel crushing features, and conchoidal crushing features (ccf), ( e ) subparallel conchoidal fractures, conchoidal fractures, and crushing features, ( f ) close-up
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Scanning electron microscope (SEM) images of quartz grains showing microtextures. For sample locations, see Figure 5A. (A) Subangular grain with conchoidal fractures (1) and fracture faces (3) (sample PG-23). (B) Grain with conchoidal fractures (1) and fracture faces (3) (sample PG-23). (C) Subangular grain with conchoidal fractures (1), fracture faces (3), and linear steps (5) (sample PG-23). (D) Angular grain with conchoidal fractures (1), fracture faces (3), and linear steps (5) (sample PG-22). (E) Subangular grain with conchoidal fractures (1) and fracture faces (3) (sample PG 21). (F) Subangular grain with V-shaped percussion marks (2) and fracture faces (3) (sample PG-20). (G) Same grain with close-up of V-shaped percussion marks (2) (sample PG-20). (H) Subangular grain with conchoidal fractures (1), V-shaped percussion marks (2), and two straight grooves (6) (sample PG-20). (I) Grain with conchoidal fractures (1), V-shaped percussion marks (2), and conchoidal crushing features (4) (sample PG-20). (J) Grain with zoomed V-shaped percussion marks (2) (sample PG-21).

Scanning electron microscope (SEM) images of quartz grains showing microtex...

Published: 01 January 2016
Figure 7. Scanning electron microscope (SEM) images of quartz grains showing microtextures. For sample locations, see Figure 5A . (A) Subangular grain with conchoidal fractures (1) and fracture faces (3) (sample PG-23). (B) Grain with conchoidal fractures (1) and fracture faces (3) (sample PG-23
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Field emission scanning electron microscope (FESEM) images of ice-rafted debris (IRD): (A) IRD (position +0.05 m, Fig. 2B), with angular edges (1) and conchoidal fractures (2). (B) Close-up view of D, showing parallel grooves and trails of transverse and lunate gouges. (C) Detail of B showing curved grooves, striations, and transverse straight and lunate gouges. (D) IRD (position +0.05 m, Fig. 2B), showing angular edges (1), grooves and striations (2), and conchoidal fractures (3). (E) Close-up view of D, showing groove with transverse gouges (1) and straight and curved grooves (2). (F) Sand-sized dropstone with conchoidal structures encased in black shales (position –1.0 m, Fig. 2B). Arrows indicate drape of lamination covering dropstone protrusion. (G) Detail of F, showing conchoidal fractures (1) with arcuate steps, onlapping and drape of overlying lamination (2), and fracture (3) postdating conchoidal fractures.

Field emission scanning electron microscope (FESEM) images of ice-rafted de...

Published: 10 October 2023
Figure 3. Field emission scanning electron microscope (FESEM) images of ice-rafted debris (IRD): (A) IRD (position +0.05 m, Fig. 2B ), with angular edges (1) and conchoidal fractures (2). (B) Close-up view of D, showing parallel grooves and trails of transverse and lunate gouges. (C) Detail of B
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Scanning electron microscopy of quartz grain from sediments of Lake A. A1: Sub-round, sub-spherical grain with polished surface and grooves. A2: Highly angular with large conchoidal fractures. A3: Prolate, highly angular, fractured plate. A4: Prolate, sub-round, precipitation feature. A5: Prolate, angular, large and small conchoidal fractures. A6: Imbricate blocks and fractured plates. A7: Angular, fractured plate. A8: Highly angular, large and small conchoidal fractures.

Scanning electron microscopy of quartz grain from sediments of Lake A. A1:...

Published: 01 June 2018
Fig.14. Scanning electron microscopy of quartz grain from sediments of Lake A. A1: Sub-round, sub-spherical grain with polished surface and grooves. A2: Highly angular with large conchoidal fractures. A3: Prolate, highly angular, fractured plate. A4: Prolate, sub-round, precipitation
Journal Article

Provenance of Beach Sands in the Northern Gulf of Guinea, SW Cameroon

Annick Kwewouo Janpou, Armel Zacharie Ekoa Bessa, Roger Firmin Donald Ntouala, Tebogo Kelepile, Gabriel Ngueutchoua, John S. Armstrong-Altrin
Published: 01 January 2024
Jour. Geol. Soc. India (2024) 100 (1): 99–114.
DOI: https://doi.org/10.17491/jgsi/2024/172987
.... The characteristics of microporosity, iron oxide inclusions, conchoidal fracture, heavy mineral grains, and opaque minerals support this proximal source. The conchoidal fractures defining the angularity of these beach sediments would suggest its derivation from crystalline rocks. The predominance of heavy minerals...
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Scanning electron microscopy images of microdebitage and naturally occurring quartz particles. A–C: Microdebitage from core RIL 10 showing characteristic angular grains with conchoidal fractures and flake scars. Note conchoidal fractures and lack of surface weathering. D: Quartz microdebitage from McIntyre land site. E, F: Naturally occurring angular quartz grains from RIL 10. Note weathered and pitted surfaces and lack of conchoidal fractures.

Scanning electron microscopy images of microdebitage and naturally occurrin...

Published: 01 July 2011
Figure 4. Scanning electron microscopy images of microdebitage and naturally occurring quartz particles. A–C: Microdebitage from core RIL 10 showing characteristic angular grains with conchoidal fractures and flake scars. Note conchoidal fractures and lack of surface weathering. D: Quartz
Journal Article

Grain-surface textures of late Wisconsinan sands from the Canadian Beaufort Shelf

Philip R. Hill, Odette C. Nadeau
Published: 01 December 1984
Journal of Sedimentary Research (1984) 54 (4): 1349–1357.
DOI: https://doi.org/10.1306/212F85D5-2B24-11D7-8648000102C1865D
... fractures; (b) angular grains with conchoidal fractures modified by solution/precipitation and edge abrasion; (c) irregularly shaped, rounded grains with mechanical v-marks and linear grooves; (d) well-rounded grains with dish-shaped concavities and upturned plates; and (e) type C and D grains with large...
View PDF for article title, Grain-surface textures of late Wisconsinan sands from the Canadian Beaufort Shelf
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Journal Article

Sub-Solidus Relations in the System PbS-CdS

Philip M. Bethke, Paul B. Barton, Jr.
Published: 01 December 1971
American Mineralogist (1971) 56 (11-12): 2034–2039.
..., is a linear function of composition. The relationship between unit-cell volume (in cubic Å) and composition is: mole percent Cds = 209.151 − V 0.4389 this relationship describes the data to ±0.16 mole percent CdS (2σ). Conchoidal fracture replaces cubic cleavage as the principal mechanism of fracture as CdS...
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Journal Article

Hereroite and vladkrivovichevite: two novel lead oxychlorides from the Kombat mine, Namibia

R. Turner, O. I. Siidra, M. S. Rumsey, S. V. Krivovichev, C. J. Stanley, J. Spratt
Published: 01 August 2012
Mineralogical Magazine (2012) 76 (4): 883–890.
DOI: https://doi.org/10.1180/minmag.2012.076.4.05
... parting or cleavage and has a conchoidal fracture. The calculated density is 8.15 g cm −3 . The mean refractive index in air at 589 nm is 2.38. The six strongest reflections in the X-ray powder diffraction pattern [ d in Å, ( I ), ( hkl )] are as follows: 2.982(100)(55İ1); 2.795(47)(802İ); 1.986(24)(88İ2İ...
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Scanning electron microscopy of quartz grain from sediments of Lake B. B1: Sub-spherical, angular, high relief. B2: Prolate, angular, large conchoidal fractures. B3: Sub-spherical, angular, adhered particle. B4: Prolate, sub-angular, fractured plate. B5: High angular, breakage block. B6: Large conchoidal fractures, angular, adhered particle. B7: Sub-spherical, angular, fractured plates. B8: Bladed angular, fractured plate, breakage block.

Scanning electron microscopy of quartz grain from sediments of Lake B. B1:...

Published: 01 June 2018
Fig.15. Scanning electron microscopy of quartz grain from sediments of Lake B. B1: Sub-spherical, angular, high relief. B2: Prolate, angular, large conchoidal fractures. B3: Sub-spherical, angular, adhered particle. B4: Prolate, sub-angular, fractured plate. B5: High angular, breakage
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Selected textures documented in this study. (A) Subangular grain with abrasion features (af) covering the top of the grain and surface showing upturned plate (up). (B) Grain with multiple breakage blocks (bb) characterized by a block of material removed from the grain. (C) Subangular grain with a very clear fracture face (ff) characterized by a large and smooth face. (D) Close-up view of subparallel linear fractures (slf). (E) Angular grain with multiple large conchoidal fractures (cf) and linear steps (ls). (F) Grain showing the occurrence of both precipitation features (pf) and dissolution etching (de) in close proximity. (G) Angular grain with a crescentic gauge (crg), arc-shaped steps (as), and linear steps (ls). (H) Subangular grain with multiple conchoidal fractures (cf) along a rounded edge (er), along with linear steps (ls) and dissolution etching (de). (I) Angular grain uncommonly devoid of any chemical features displaying fresh surfaces in the form of fractures faces (ff). Also displays conchoidal fractures (cf), linear steps (fs), subparallel linear fractures (slf), and sharp angular features (saf).

Selected textures documented in this study. (A) Subangular grain with abras...

Published: 02 March 2018
grain with a very clear fracture face (ff) characterized by a large and smooth face. (D) Close-up view of subparallel linear fractures (slf). (E) Angular grain with multiple large conchoidal fractures (cf) and linear steps (ls). (F) Grain showing the occurrence of both precipitation features (pf
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Scanning electron microscope micrographs of grains from Ocean Drilling Program Site 696. (A) Grain type A with an angular outline, high relief, large conchoidal fracture, subparallel linear fracture, straight steps, fracture face, straight groove, and solution pits. (B) Grain type A with a subangular outline, medium relief, large conchoidal fracture, subparallel linear fracture, and adhering particles. (C) Grain type B with a subangular outline, medium relief, dissolution weathering, and adhering particles. (D) Grain type B with subangular outline, medium relief, dissolution weathering, adhering particles, and granular precipitation. (E) Grain type C with a subrounded outline, medium relief, and upturned plates. (F) Grain type D with an angular outline, low relief, euhedral overgrowth, and dissolution etching. (G) Grain type E with a rounded outline, medium relief, dissolution weathering, and edge abrasion. (H) Grain type E with a subrounded outline, medium relief, irregular dish-shaped depressions, impact craters, solution pits, granular precipitation, and a bulbous feature. AP—adhering particles; DW—dissolution weathering; GP—granular precipitation; UP—upturned plates; EU—euhedral overgrowth; DE—dissolution etching; EA—edge abrasion; IC—impact craters; SP—solution pits; BF—bulbous feature; ID—irregular dish-shaped depression; SS—straight steps; LCF—large conchoidal fracture (>10 µm); SLF—subparallel linear fracture; FF—fracture face; SG—straight groove.

Scanning electron microscope micrographs of grains from Ocean Drilling Prog...

Published: 14 May 2024
Figure 2. Scanning electron microscope micrographs of grains from Ocean Drilling Program Site 696. (A) Grain type A with an angular outline, high relief, large conchoidal fracture, subparallel linear fracture, straight steps, fracture face, straight groove, and solution pits. (B) Grain type
Journal Article

Early Miocene European loess: A new record of aridity in southern Europe

Davor Pavelić, Marijan Kovačić, Adriano Banak, Gonzalo Jiménez-Moreno, Frane Marković, Kristina Pikelj, Alan Vranjković, Lucija Premužak, Darko Tibljaš, Mirko Belak
Journal: GSA Bulletin
Published: 01 January 2016
GSA Bulletin (2016) 128 (1-2): 110–121.
DOI: https://doi.org/10.1130/B31280.1
...Figure 7. Scanning electron microscope (SEM) images of quartz grains showing microtextures. For sample locations, see Figure 5A . (A) Subangular grain with conchoidal fractures (1) and fracture faces (3) (sample PG-23). (B) Grain with conchoidal fractures (1) and fracture faces (3) (sample PG-23...
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Bobcookite, NaAl(UO 2 ) 2 (SO 4 ) 4 ·18H 2 O and wetherillite, Na 2 Mg(UO 2 ) 2 (SO 4 ) 4 ·18H 2 O, two new uranyl sulfate minerals from the Blue Lizard mine, San Juan County, Utah, USA

Anthony R. Kampf, Jakub Plášil, Anatoly V. Kasatkin, Joe Marty
Published: 01 June 2015
Mineralogical Magazine (2015) 79 (3): 695–714.
DOI: https://doi.org/10.1180/minmag.2015.079.3.14
... fluorescence; pale greenish yellow streak; hardness (Mohs) 2½; brittle; conchoidal fracture; no cleavage; moderately hygroscopic; easily soluble in cold H 2 O; density calc = 2.669 g cm −3 . Optically, biaxial (–), α = 1.501(1), β = 1.523(1), γ = 1.536(1) (white light); 2V meas. = 78(1)°; 2V calc. = 74...
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View PDF for article title, Bobcookite, NaAl(UO 2 ) 2 (SO 4 ) 4 ·18H 2 O and wetherillite, Na 2 Mg(UO 2 ) 2 (SO 4 ) 4 ·18H 2 O, two new uranyl sulfate minerals from the Blue Lizard mine, San Juan County, Utah, USA
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Image
SEM images of selected quartz grains from the proximal lacustrine facies in the Cutler Formation. A) Angular quartz grain displays numerous high-stress fractures such as a straight groove (sg), crescentic gouge (crg), and mechanically upturned plate (mup). Subparallel linear fractures (sf), conchoidal fracture (cf), adhering particles (ap), and precipitation features (pf) are also present. B) Angular quartz grain displaying a deep trough (dt) and straight groove (sg) as well as subparallel linear fractures (sf), conchoidal fractures (cf), and precipitation features (pf). C) Quartz grain with abundant precipitation superimposed on a curved groove (cg) and deep troughs (dt). See Table 1 for explanation of microtextures.

SEM images of selected quartz grains from the proximal lacustrine facies in...

Published: 01 November 2015
(sf), conchoidal fracture (cf), adhering particles (ap), and precipitation features (pf) are also present. B) Angular quartz grain displaying a deep trough (dt) and straight groove (sg) as well as subparallel linear fractures (sf), conchoidal fractures (cf), and precipitation features (pf). C