If you live in the country on a farm or large section, you may have your own pumice supply. Check out any area that dries out quickly in the summer. There may be pumice just a spades depth under the surface. Around the Central North Island Volcanic plateau stretching from the central mountains, through Taupo, Rotorua, Tokoroa, the Bay of Plenty, Waihi to Opotiki and west to parts of Hawkes Bay, pumice has been deposited over the millennia from the eruptions of the Central Volcanoes. N.W. The eruption of Tarawera in the 1880's added more volcanic material, mostly ash over the Bay of Plenty.
Pumice comes in many shades from cream through to orange.
You can see it on Rainbow Mountain. Many thanks to Elsie G for the above article. The Mid Year Executive meeting held in Hastings during July, was successful in working through a long agenda on behalf of the Society. A report will be given at the August Meeting. Then Only Left Handers are in their Right Minds.