AHE pebbles comes in 3 types: Natural, Tumbled and Polished.
Natural pebbles are collected and quarried from riverine and ocean where there are abundance of gravels. Nonetheless, as some governmental organizations has limited the exports of these natural gravels, supply becomes quite inconsistent. Nonetheless, AHE only collects pebbles from legally approved areas, and does not make use of child labor.
Tumbled pebbles are done in line with environmental purpose and recycling of excessive materials from the produced stones and smaller boulders.
AHE is an environmental conscious organization and wish to provide the best working materials which can be used by everyone with a peace of mind.
Sizes of gravels range from 3~5mm, 5~8mm, 8~10mm, 10~30mm, 30~50mm, 50~80mm up to boulder size for landscape purpose. Quality is enforced based on Japanese standards.