“...Joons are a highly silicified material from the southernrmost part of the South Island. They can be found within a rough triangle from Gore to Awarua Bay and across to Tokanui. Some believe the material to be a highly silicified forest floor but there is no evidence of plant material discernible in any of the pieces I have seen. They are mainly yellow/brown/grey tones but pink and blues are not uncommon.
The name joon was coined by John Earle and Gordon Auton.
At Awarua Bay the stones are covered with an iron staining and often the only way to distinguish them from all the other estuary stones is to look for the tell tale fingernail or thumbnail imprint on the surface...”
personal report from Malcolm Luxton, Canterbury