Yn ôl yr ystadegau, yn 1827 y
darganfuwyd y manganîs cyntaf yn ardal y Rhiw ac mewn ffrwd fechan, sef ffrwd y Nant. Nid oes cofnod yn dweud ai trwy ddamwain ynteu trwy ymchwiliad y bu i’r manganîs ddod i’r amlwg.

Darganfeuwyd 28 wahanol math o mwynau yn Rhiw, sef-
Oxides a Hydroxides, Nitrates, Carbonates a Borates, Sulphates, Chromates, Molybdates,Tungstates a Silicates.

Ni ellir dod o hyd i rhai o rhain yn unman arall yn Prydain, ac y mae ambell un 'mond ar gael yn Rhiw.

Mae yna un mwyn yn unigryw i waith Benallt, Rhiw sef -

It was at Ffrwd Y Nant that manganese was first discovered in Rhiw as late as 1827. There are, however, no reports as to if the discovery was by chance or through prospecting.

There have been 28 different classified minerals found at Rhiw, including-
Oxides and Hydroxides, Nitrates, Carbonates and Borates, Sulphates, Chromates, Molybdates,Tungstates and Silicates.

Some of the minerals can be found nowhere else in Britain and some nowhere else in the world.

Of these, one true mineral only occurs in Rhiw at Benallt namely-

Paracelsian - BaAl2Si2O8

Group of paracelsian crystals, large doubly terminated crystal 50mm.

Ian Jones collection, ex collection Natural History Museum, London. Obtained from Sir Arthur Russell 1941, collected 1919.

Piemontite - Ca2 (Mn,Fe)Al2Si3O12OH

1mm crystals. Steve Rust photo & collection

Y Mae yna 4 mwyn 'lleol'-                    There are also 4 recognized type localities-

Cymrite - BaAl2Si2(O,OH)8·H2O
Darganfeuwyd / Discovered in 1949

Banalsite - BaNa2Al4Si4O16
Darganfeuwyd / Discovered in 1944

Bannisterite - (K,Ca)0.5(Mn,Fe,Zn)4(Si,Al)7 O14(OH)8
Darganfeuwyd / Discovered in 1968

Pennantite - (Mn5Al)(Si3Al)O10(OH)8
Darganfeuwyd / Discovered in 1946

Cafodd manganîs ei ddarganfod ym Mhrydain cyn belled yn ôl â 1774 a buan iawn y dysgwyd am ei rinweddau. Gellir ei ddefnyddio i galedu haearn, a’r sodiwm a’r potasiwm sydd ynddo i gynhyrchu diheintydd.

Hanes Mwynfeuydd Rhiw

Cofrestr 1908-1918

Manganese was discovered in Britain as early as 1774 and its properties were soon found. It can be used to strengthen iron, and the Sodium and Potassium it contains can be used in the production of disinfectants.

Mining History at Rhiw

Mining Registers 1908-1918

Adfeilion Baron Hill Ruins

Hanes Diwydiant

Industry History