Asbestos insulation comes in many forms and can look loose, lumpy, and fluffy like wool or hardened like corrugated cardboard or pebbly, and has a gray, gray-brown, or silvery gold color.

Asbestos pipe insulation can have a sealer applied over it, and a floor can be covered with any number of materials. You asked about simply leaving it as is, which is possible but not recommended.

What Does Black Mastic Asbestos Look Like? You will only see black mastic asbestos after a floor covering has been removed. As the name suggests, black is its predominant color.