Generally, you can't tell whether a material contains asbestos simply by looking at it, unless it is labeled. If in doubt, treat the material as if it contains asbestos and leave it alone. You may want to have your home inspected for asbestos-containing materials by a trained and accredited asbestos professional if:
A trained and accredited asbestos professional should take samples for analysis, since a professional knows what to look for, and because there may be an increased health risk if fibers are released. In fact, if done incorrectly, sampling can be more hazardous than leaving the material alone. Taking samples yourself is not recommended.
If building materials in your home aren’t damaged and won’t be disturbed, you do not need to have your home tested for asbestos. Material that is in good condition and will not be disturbed (by remodeling, for example) should be left alone.
If you think there may be asbestos in your home, don’t panic.
Asbestos-containing materials that aren’t damaged or disturbed are not likely to pose a health risk. Usually the best thing is to leave asbestos-containing material alone if it is in good condition.
Generally, asbestos-containing material that is in good condition and will not be disturbed (by remodeling, for example) will not release asbestos fibers.
Asbestos-containing materials may release fibers when they are disturbed, damaged, removed improperly, repaired, cut, torn, sanded, sawed, drilled or scraped. Keep an eye on asbestos-containing materials and visually check them over time for signs of wear or damage.
If you suspect material contains asbestos, don't touch it. Look for signs of wear or damage such as tears, abrasions, or water damage. Damaged material may release asbestos fibers. This is particularly true if you often disturb it by hitting, rubbing or handling, or if it is exposed to extreme vibration or air flow.
For slightly damaged asbestos-containing material, sometimes the best way to deal with it is to limit access to the area and not to touch or disturb it. If asbestos-containing material is more than slightly damaged or if you are going to make changes in your home that might disturb it, repair or removal by a trained and accredited asbestos professional is needed.
Sources to read more about asbestos: