From the GeoWhen Database:

                               Rhyacian Period

                       From 2300 +/- 0 To 2050 +/- 0 Ma

 Start Defined By:  Fixed Date
 End Defined By:  Fixed Date

 Start Based On:  Gradstein, Ogg, Smith, et. al., _A Geologic Time Scale 2004_
 End Based On:  Gradstein, Ogg, Smith, et. al., _A Geologic Time Scale 2004_

-- Overlaps With --
 General Stage: Animikean  (2225 - 1400)

-- A Substage of --
 Time:          Precambrian      (4567.17 - 542)
 Eon:           Proterozoic      (2500 - 542)
 General Stage: Huronian          (2500 - 1400)
 Era:           Paleoproterozoic (2500 - 1600)
 Chinese Stage: Luliangian        (2350 - 1750)

-- Preceded By --
 Period: Siderian  (2500 - 2300)

-- Followed By --
 Period: Orosirian  (2050 - 1800)