Abstract
Bentonite deposit occurs as lenticular or podiform beds interstratified within the Middle Miocene Toledo Formation, in Balamban, Cebu Province, Philippines. Some selected bentonite samples collected from available field outcrops were examined using x-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetric (TG), scanning electron microscopy (SEM), infrared (IR) and electron diffraction x-ray (EDX) analytical techniques. Laboratory data and results yield that the clay constitution of the bentonite is principally smectite minerals. Some samples also indicate interstratified kaolinite/smectite. Kaolin and zeolite (probably clinoptilolite) are associated in minor amount. The non-phyllosilicates assemblage is dominantly of crystalline quarts, feldspar and calcite.
