COLEMAN QUARTZ MINE
The Ouachita Mountains of Arkansas were formed during the Late Paleozoic Ouachita Orogeny. That mountain forming event was accompanied by the intrusion of hydrothermal quartz veins in some areas. The Coleman Quartz Mine allows for close examination and collection of spectacular quartz crystals from these veins.
Ouachita Mountains - the Ouachita Orogenic Belt of Arkansas consists principally of folded & faulted Paleozoic sedimentary rocks. The mountains do not have high topographic relief because of their age. The Ouachitas formed during the Late Pennsylvanian and Permian. Two hundred and fifty million years worth of weathering and erosion has reduced them considerably.
Coleman Quartz Mine - the main pit. Rocks are excavated from the pit by heavy machinery and dumped on an adjacent platform for collecting.
Location: Coleman Quartz Mine, south of Jessieville, northern Garland County, west-central Arkansas, USA. 34º 39.700' N, 93º 06.072' W.
Coleman Quartz Mine - wall of the main pit showing abundant hydrothermal quartz veins (whitish) intruding quartz arenites of the Middle Ordovician Blakely Sandstone. The quartz veins are Late Pennsylvanian to Permian in age.
Coleman Quartz Mine - large masses of hydrothermal vein quartz (SiO2).
Hydrothermal vein quartz (white - SiO2) of Late Pennsylanian-Permian age intruding quartz arenite (brown) of the Blakely Sandstone (Middle Ordovician).
Hydrothermal quartz vein having abundant, well-formed crystal faces and crystal terminations.
Hydrothermal vein quartz (white) intruding quartz arenites (light brown) of the Blakely Sandstone (Middle Ordovician).
Hydrothermal quartz vein having abundant, large crystals.
Hydrothermal quartz vein (white; Late Pennsylvanian-Permian) intruding quartz arenite (brown; Blakely Sandstone, Middle Ordovician). Sample is 4.1 cm tall.
Hydrothermal quartz vein (whitish; Late Pennsylvanian-Permian) intruding quartz arenite (brown; Blakely Sandstone, Middle Ordovician). Field of view: 4.3 cm across.
Quartz arenite from the Middle Ordovician Blakely Sandstone. Very thin hydrothermal quartz veins (whitish-gray wisps) of Late Pennsylvanian-Permian age are present throughout the rock. Field of view: 2.55 cm across.
Quartz (SiO2) (4.2 cm tall) from hydrothermal vein intruding Blakely Sandstone. Well-formed hexagonal quartz crystals are common at Coleman Mine. The crystals are clear/colorless (“rock crystal”) or whitish (“milky quartz”).