Agates from precambrian rocks (older than 570 mA) are rare and the rocks of the Lake Superior region are usually stated as world-wide oldest hostrock of agates. In addition, agates are found in the Pilbara block in Western Australia. The Pilbara rocks can reach an age up to 3.5 billion years and are thereby the oldest rocks on earth at all.
Terry Moxon writes (in the book “agates” from the Bode publishing house 2005):
“... The Maddina basalt within the range Pilbara is dated with 2720 mA. HICKMAN (1983) describes the occurrence of agates in these old rocks. Newest investigations show a advanced crystallinity (MOXON etal., in the pressure) with the analysis of agates from the Pilbara block. It is possible that similar descriptions of agates in such old rocks (> Seem to 2500 mA) also in the Russian or Chinese scientific literature. Present it is not yet possible to link the age of these agates with the age of its host-rock securely, but, …. usually agates are formed by events, which took plac only few millions years after the formation of the host-rocks...”