1998 Volume 8 Pages 95-100
The occurrence of apatite was confirmed in three unweathered andesite and rhyolite tephras from the northern part of Japan. The apatite mineral was identified using a scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDX). The apatite mostly occurred as inclusions in the heavy minerals. The apatite was soluble in an acidic soil testing solution (Truog method) to determine plant-available phosphorus (P) in the soil.