The Collaborative International Dictionary of English v.0.48:

Amygdaloid \A*myg"da*loid\, Amygdaloidal \A*myg`da*loid"al\, a.
   1. Almond-shaped.
      [1913 Webster]

   2. Pertaining to, or having the nature of, the rock
      amygdaloid.
      [1913 Webster]

WordNet (r) 3.0 (2006):

amygdaloidal
    adj 1: shaped like an almond [syn: almond-shaped,
           amygdaliform, amygdaloid, amygdaloidal]