So, I have read in a grammar book that the participles and transgressives in russian are used mainly in the written language and normally not used in conversation. Is this true? Are they used in conversation and if they are, is it a common practice?
No, this is not true. It’s not easy to say something like разбитое стекло, обтягивающее белье, дрожащие руки, лоснящаяся кожа, текущий кран; придти не предупредив, отвечать не думая and so on without using participles (причастия) and transgressives (деепричастия).
Participle and transgressive clauses (причастные и деепричастные обороты) are less common in conversations than in the written language, yes. But the matter is not in parts of speech – any subordinate clauses are rare in colloquial language, because it’s easier to lose train of thought listening sentences with complicated syntax rather than reading it.