What is ......Dust? I know this is quite ackward and may not be the right place to ask such a question but I am a bit curious to know something good about it: Earth is composed of soil; Soil is a mixture of elements and compounds; But we don't use the soil around us to extract those compounds and use them in lab, neither do we pay much importance to it; Then comes dust; pretty much the same story. So the thing we call dust: What is its atomic number and properties. Then comes the last question What is stellar dust, its composition, properties etc.?