The Collaborative International Dictionary of English v.0.48:

Chalky \Chalk"y\, a.
   Consisting of, or resembling, chalk; containing chalk; as, a
   chalky cliff; a chalky taste.
   [1913 Webster]

WordNet (r) 3.0 (2006):

chalky
    adj 1: composed of or containing or resembling calcium carbonate
           or calcite or chalk [syn: calcareous, chalky]
    2: of something having the color of chalk; "she turned chalky
       white"

Moby Thesaurus II by Grady Ward, 1.0:

63 Moby Thesaurus words for "chalky":
   argent, argentine, branny, canescent, chalklike, comminute,
   comminuted, cretaceous, crushed, detrital, detrited, disintegrated,
   dusty, efflorescent, farinaceous, fine, flaky, fleecy-white,
   floury, frosted, frosty, furfuraceous, gone to dust, grated,
   grizzled, grizzly, ground, hoar, hoary, impalpable, lactescent,
   levigated, lily-white, marble, marmoreal, mealy, milky, milled,
   niveous, pestled, platinum, powdered, powdery, pulverant,
   pulverized, pulverulent, pure white, reduced to powder, scaly,
   scobicular, scobiform, scurfy, sharded, shredded, silver, silvered,
   silvery, snow-white, snowy, swan-white, triturated, white,
   white as snow