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Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases, [1] [2] is an opaque, [3] impure variety of silica, usually red, yellow, brown or green in color; and rarely blue. The common red color is due to iron(III) inclusions. Jasper breaks with a smooth surface and is used for ornamentation or as ...
Photo of radiolarite in Corsica, France (text in French) retrieved 2009-05-17 This page was last edited on 6 December 2024, at 00:40 (UTC). Text is available under ...
Orbicular jasper from Madagascar. Orbicular jasper is a variety of jasper which contains variably-colored orbs or spherical inclusions or zones. In highly silicified rhyolite or tuff, quartz and feldspar crystallize in radial aggregates of needle-like crystals which provide the basis or seed for the orbicular structure seen in this kind of jasper. [1]
Breccia is composed of coarse rock fragments held together by cement or a fine-grained matrix. [5] Like conglomerate, breccia contains at least 30 percent of gravel-sized particles (particles over 2mm in size), but it is distinguished from conglomerate because the rock fragments have sharp edges that have not been worn down. [6]
Biggs jasper is a variety of the mineral jasper. It is a "picture jasper" – a jasper that exhibits particular patterns and colors – and is used as an opaque gemstone . [ 1 ] It exhibits intricate, shell- or layer-like patterns in shades of brown ranging from beige to dark brown.
Volcanogenic massive sulfide ore deposit at Kidd Mine, Timmins, Ontario, Canada, formed 2.7 billion years ago on an ancient seafloor A cross-section of a typical volcanogenic massive sulfide (VMS) ore deposit as seen in the sedimentary record [1]
Serpentine from Poland. Serpentine subgroup (part of the kaolinite-serpentine group in the category of phyllosilicates) [1] are greenish, brownish, or spotted minerals commonly found in serpentinite.