diff --git a/docs/source/io_formats/materials.rst b/docs/source/io_formats/materials.rst
index 286342a2b..5f0aa3a5e 100644
--- a/docs/source/io_formats/materials.rst
+++ b/docs/source/io_formats/materials.rst
@@ -112,7 +112,7 @@ Each ``material`` element can have the following attributes or sub-elements:
     is the name of the S(a,b) table that should be associated with the material.
     There is also an optional ``fraction`` element which indicates what fraction
     of the relevant nuclides will be affected by the S(a,b) table (e.g. which
-    fraction of a material is crystaline versus amorphus).  ``fraction``
+    fraction of a material is crystalline versus amorphous).  ``fraction``
     defaults to unity.
 
     *Default*: None
diff --git a/openmc/material.py b/openmc/material.py
index 6ac153c86..24cd3343a 100644
--- a/openmc/material.py
+++ b/openmc/material.py
@@ -628,7 +628,7 @@ class Material(IDManagerMixin):
         fraction : float
             The fraction of relevant nuclei that are affected by the
             :math:`S(\alpha,\beta)` table.  For example, if the material is a
-            block of carbon that is 60% graphite and 40% amorphus then add a
+            block of carbon that is 60% graphite and 40% amorphous then add a
             graphite :math:`S(\alpha,\beta)` table with fraction=0.6.
 
         """