  We report measurements and theoretical analysis of resonant spin tunneling in
randomly oriented nanospheres of a molecular magnet. Amorphous nanospheres of
Mn$_{12}$ acetate have been fabricated and characterized by chemical, infrared,
TEM, X-ray, and magnetic methods. Magnetic measurements have revealed sharp
tunneling peaks in the field derivative of the magnetization that occur at the
typical resonant field values for Mn$_{12}$ acetate. Theoretical analysis is
provided that explains these observations. We argue that resonant spin
tunneling in a molecular magnet can be established in a powder sample, without
the need for a single crystal and without aligning the easy magnetization axes
of the molecules. This is confirmed by re-analyzing the old data on a powdered
sample of non-oriented micron-size crystals of Mn$_{12}$ acetate. Our findings
can greatly simplify the selection of candidates for quantum spin tunneling
among newly synthesized molecular magnets.
