Аннотация:Abstract. Samples of Mt-microspheres of various origins,including those obtained in industrial processes, have beenstudied. The authors concluded that the morphologicalcharacteristic of Mt-microspheres only, without ofconsideration of synthesis processes, are not sufficient todiagnose their origin. The authors revealed a distinctivefeature of Mt-microspheres and other microparticles thatwere extracted from sedimentary rocks and considered ascosmogenic, it is the presence of morphology and shapescharacteristic for by-products of metal processing andtarget products of plasma chemical synthesis.