The enamel is harder, as it's made up of very hard, calcified epithelially derived tissue.  It covers the dentin located in the crown portion (projects through the gum).  The enamel actually protects the dentin.  Dentin is made up of a special type of calcified connective tissue.  Also, calcified connective tissue, the cementum covers the root portion.  
Hope this helps.
Mary
 

Mary  Stevens BS, HT(ASCP)
Bone Histology Supervisor
Genetics Institutue
1 Burtt Road
Andover, MA  01810
phone 978-247-1667
fax 978-247-1389

>>> Jason Burrill <jburrill@MIT.EDU> - 8/4/1999 6:58 AM >>>
Does anyone know which is harder dentin or enamel?  Thanks
Jason Burrill 
Histology Supervisor
Massachusetts Institute of Technology
jburrill@mit.edu