Unless material is labeled as containing asbestos the naked eye can not tell if the material contains asbestos.
A certified professional should do the testing as incorrect sampling can cause fibers to be released.
Information resources about asbestos can be found at http://epa.gov/asbestos/pubs/ashome.html
Peter Meer is President/Broker of Meer & Company, Inc., 303-322-1550, which manages 150 single family homes and properties in Denver, Colorado. He holds the Master Property Manager (MPM) designation and the firm holds the Certified Residential Management Company (CRMC) designation from the National Association of Residential Property Managers (NARPM). To learn more about Peter's Landlord solutions visit Meer and Company website at www.meerandco.com