Show Mica Mica so named from its be being ng easily ily divided into glistening scales s consists consists consists con con- of silica and associated with ma magnesia esla soda and lime In varyIng varying vary vary- ing hag proportions Thus we have potash mica consisting of silica mca and potash and magnesia mica in which tile the Is partially replaced by magnesia passing as passing as the proportion of ot magnesia Into increases increases into soft talc which is chiefly composed of silica and ma magnesia esla |