Guess the Cover of American Laboratory—September 2013

Correctly identify this month’s cover image and be entered to win a $10 Amazon gift card (one entry per person; you must be 18 years of age to be eligible. See contest rules at

Hint: Its ultrahigh porosity makes it so light it is popular with manufacturers of orthopedic devices and automobiles, yet in music it is known to be heavy. The image on this month’s cover was captured using SEM imaging, original magnification 100×.

What do you think it is? Enter by leaving your answer in the comments section below. Stay tuned for the answer and for next month’s cover image!