Llanite
Photographed by Michael P. Klimetz
[Polished Slab]
Llano County
TEXAS
Photographed by Michael P. Klimetz
[Rough Slab]
Llano County
TEXAS
Photographed by Michael P. Klimetz
[Polished Slab]
Llano County
TEXAS
Llanite is a porphyritic rhyolite that is primarily gray in color, with blue quartz and reddish microcline microperthite phenocrysts. It has a fine-grained groundmass of brown biotite mica crystals, feldspar, and microcrystalline quartz. It is a Precambrian felsic extrusive rock that is found in Llano County, Texas. It is named after the Llano Uplift in central Texas, where it is found. Although similar rocks are found elsewhere in the world, its name is only used to refer to the variety found in this location. It is also known as Llanite Quartz or Llanite Blue Quartz. It is comprised of feldspar, blue quartz, biotite, and trace amounts of other minerals.
