The Collaborative International Dictionary of English v.0.48:

Gem \Gem\ v. t. [imp. & p. p. Gemmed; p. pr. & vb. n.
   Gemming]
   1. To put forth in the form of buds. "Gemmed their blossoms."
      [R.] --Milton.
      [1913 Webster]

   2. To adorn with gems or precious stones.
      [1913 Webster]

   3. To embellish or adorn, as with gems; as, a foliage gemmed
      with dewdrops.
      [1913 Webster]

            England is . . . gemmed with castles and palaces.
                                                  --W. Irving.
      [1913 Webster]

WordNet (r) 3.0 (2006):

gemmed
    adj 1: covered with beads or jewels or sequins [syn: beady,
           gemmed, jeweled, jewelled, sequined, spangled,
           spangly]