Mi(ni)Geo

Las esferulitas son pequeños cuerpos esféricos que normalmente aparecen en rocas ígneas ricas en vidrio, sobretodo en riolitas ricas en sílice, aunque también aparecen en obsidianas. A menudo cuentan con una estructura radial provocada por el intercrecimiento de cristales de cuarzo y ortoclasa. Se piensa que estas formas ocurren cuando ocurre un crecimiento mineral muy rápido tras la nucleación. (via Un geólogo en apuros)

Silver and copper (by FEI Company)

Silver particles and perfect copper crystals. Courtesy of Wadah Mahmoud.

Gold ore (Callion/Australia). Native gold in association with colloform goethite indicates contemporaneous precipitation. Width of micro-photo corresponds to approx. 250 microns. (via Geneva Ore Deposits Group)

Image taken through [Opportunity’s] microscope of the plate of bedrock it studied a few sols back. (via The Road To Endeavour)

Chalcedony. Photomicrograph. Light: XPL. Objective: x2.5. (via GeoScenic)

Egyptian Nano Pyramids (by FEI Company)

Three copper crystals like egyptian pyramids. Courtesy of Wadah Mahmoud.

gas shale (by FEI Company)

FEI Helios NanoLab 650 SEM image of fine grained sedimentary rock (gas shale). Image was collected at sub-1 keV with secondary electrons.

Iron nodules from soil (by FEI Company)

Courtesy of Wadah Mahmoud.

Radiolaria Polycystinea (by FEI Company)

Fossilized, ancient single cell organism, from the Barbados Islands. Imaged in low vacuum mode after having received a thin gold coating. Courtesy of Linnea Rundgren.

Glacial Shell (by FEI Company)

The image was done from a seashell. Courtesy of Wesller Schmidt.

ESEM - Calcium sulfphate dihydrate. (by FEI Company)

The hydration of calcium sulphate hemihydrate (CaSO4.0,5H2O) leads to gypsum (calcium sulphate dihydrate – CaSO4.2H2O). It is a highly exothermic reaction which occurs by a dissolution/reprecipitation mechanism: when the hemihydrate is mixed with water, a fraction of it dissolves to give a saturated solution with respect to Ca2+ and SO4 2- ions, which is supersaturated with respect to calcium sulfphate dihydrate leading to nucleation and crystal growth. ESEM images taken from the hemihydrate hydration process. One can follow water adsorption to the hemihydrate at a 100% RH and the resulting needle-like crystals which result after water elimination. Courtesy of Francisco Rangel.

This is a picture of an ooid grainstone, which has been stained so that calcite shows red (taken under 4x). The point of interest here is the beautiful porcellaneous foram in the upper right. The white splotches in it are chalcedony replacement. The ooids are undergoing internal dissolution, which is why they show blue voids inside; because of this the rock has abundant secondary porosity. The lower portion of the slide contains several deformed ooids, and a fracture with clear movement on it cuts across the mid to lower right side. (via katsuhiro - Picasa Web Albums)

Dare to be Different (by FEI Company)

Pseudo-colored micrograph of a synthetically prepared calcium sulfate crystals. Material was carbon-coated and imaged under high-vacuum mode of the Quanta 200 E-SEM. Courtesy of Melina Miralles.

Ortogabro (by jvanne)

Microcanyon (by FEI Company)

Microcrack after bending test, colored by Manuel Paller. Courtesy of Martina Dienstleder.