Palygorskite from Hanezuru, Kuzu, Tochigi Prefecture, Japan

Abstract

Palygorskite, white colour and had leather like appearance, occurred from weathered surface of dolomite block in the Hanezuru dolomite ore deposit. The material may be crystallized out in a fissure of dolomite ore deposit by action of low temterature hydrothermal solution and was exposed out on surface of the block by weathering of dolomite. The palygorskite specimen was associated with dolomite and small amount of quartz. Purified material with 4.22% dolomite was investigated. by means of chemical analysis, X-ray powder method and electron microscope. Chemical formula of this mineral was calculated from the value of which was subtructed by the weight percent of dolomite compositions and was followed:(Si_7.85A1_0.52)(Mg_2.10Al_1.72Fe³⁺_0.07Ti_0.03) Ca_0.23O_21.00 (OH) _3.58 (OH₂) _3.71·4.23H₂0. X-ray powder data of the specimen from Hanezuru agreed well with those from Lone Jack Quarry, Virginia and Attapulgus, Georgia. Electron micrographs of the specimen were shown in plates. Refracfive indices were measured as α=1.558 and γ=1.567, also.