veinlets cutting hydrothermal manganese silicate ore
(Benallt mine, Wales); in a copper-bearing deposit in
dolostones and siderites (Ruby Creek, Alaska, USA);
in jadeite graywacke near the contact of an ultramafic
rock and the Franciscan Formation (San Benito County,
California, USA); a product of high-pressure metamorphism
of manganese-rich rocks (Andros Island, Greece).
(Benallt mine, Wales); Calcite, Albite, Lawsonite (San
Benito County, California, USA); Hyalotekite, Banalsite,
Hyalophane, Hedyphane, Manganoan Biotite (Långban,
is a rare barium silicate mineral that is roughly equivalent to
hydrated Celsian and forms in barium-rich rocks under
conditions of low grade metamorphism. Cymrite was first described from
material collected in 1944 by
Dr. A.W. Groves and Dr. W. Campbell Smith at the Benallt manganese mine, near Rhiw, Llanfaelrhys, Lleyn Peninsula, Gwynedd, Wales, UK.
Cymrite is colorless
when pure but commonly dark green or light to
dark brown due to impurities. It is translucent with
vitreous to pearly luster and a Moh's hardness of 2-3.
Cymrite may show greenish
white fluorescence under UV light.
is named from
the Welsh name for Wales, the locality of its discovery.
The word Cymru is descended from the Old Brythonic word combrogi, meaning fellow-countrymen.
Old Brythonic was an ancient Celtic language spoken in Britain.
the Benallt mine, Rhiw, Lleyn Peninsula, Wales. From
Långban, Värmland, Sweden. In the USA, from
Ruby Creek, Brooks Range, Alaska, and near Pacheco Pass,
San Benito County, California. On Andros Island, Cyclades
Islands, Greece. From the Lianyuan-Shaoyang area, Hunan
Province, China. In the Shiramaru mine, Tokyo Prefecture,
Japan. At Northwest Nelson, South Island, New Zealand.
In the Saureisk deposit, Polar Ural Mountains, and near
Lake Baikal, eastern Siberia, Russia. From the Black
Rock and Hotazel mines, near Kuruman, Cape Province,
South Africa. At Kalugeri Hill, Babuna River, Jakupica
Mnts, 15 km NW of Nežilovo, Veles, Republic of Macedonia.
A number of other occurrences are known.