Mineralogical Studies of Mica Clay Minerals Associated With Roseki Deposits.

Mineralogical properties of the so-called sericite minerals associated with some Roseki deposits in some Roseki depositsthe Chugoku provinces have been investigated by X-ray diffractionchemical and thermal analytical方法. the sericite minerals constituting a typical Roseki depositthe Yagi mine in the Mitsuishi district, Okayama Prefecture，yield noticeable substitution of ammonium for interlayer potassium and variable interstratificationmontmorillonite showing a remarkable tendency to increase from silicified zone to intenselysericitized (Roseki) zone through spotted "Toseki" zone. On the contrary，the minerals occurring in a "high-temperature" type Roseki deposit of the Uku mine，yamaguchi prefecture,are well-crystallized < 2m_1 > sericite having neither interlayer substitution nor mixedlayering withmontmorillonite. The specimens from a "telescope" type Roseki deposit of The Horo mine，hiroshima prefecture,are of intermediate nature between the typical and "high-temperature " type deposits.Additionallythermal properties of these seicite minerals are to be noticed in relation to interlayersubstitution of ammonium for potassium. Usual potassium mica yield simple dehydroxylation around500-600 C. Ammonium-bearing mica, however，forms -mica structure at once by detachment of ammonia from the interlayer ammonium at 400-500 Cand then slow dehydroxylation takes place at relatively high temperature range of 700-800 C followedsubsequent transformation to mullite and silica mineral at about 1000 C. This thermal behavioraccompanied with distinctive volume constraction，这是关于一个重要的字符在utilizing as ceramic材料。

Mineralogical properties of the so-called sericite minerals associated with some Roseki deposits in the Chugoku provinces have been investigated by X-ray diffraction, chemical and thermal analytical methods.The sericite minerals constituting a typical Roseki deposit of the Yagi mine in the Mitsuishi district, Okayama Prefecture, yield noticeable substitution of ammonium for interlayer potassium and variable interstratification with montmorillonite showing a remarkable tendency to increase from silicified zone to intensely sericitized (Roseki) zone through spotted "Toseki" zone. On the contrary, the minerals occurring in a "high-temperature" type Roseki deposit of the Uku mine, Yamaguchi Prefecture, are well-crystallized <2M_1> sericite having neither interlayer substitution nor mixedlayering with montmorillonite. The specimens from a "telescope" type Roseki deposit of the Horo mine, Hiroshima Prefecture, are of intermediate nature between the typical and "high-temperature " type deposits.Additionally thermal properties of these seicite minerals are to be noticed in relation to interlayer substitution of ammonium for potassium. Usual potassium mica yield simple dehydroxylation around 500-600゜C. Ammonium-bearing mica, however, forms H-mica structure at once by detachment of ammonia from the interlayer ammonium at 400-500゜C and then slow dehydroxylation takes place at relatively high temperature range of 700-800゜C followed by subsequent transformation to mullite and silica mineral at about 1000゜C. This thermal behavior is accompanied with distinctive volume constraction, which is considered to be an important character in utilizing as ceramic materials.