diff --git a/lib/rdf/blank_node/generator.ex b/lib/rdf/blank_node/generator.ex
index 9c4e6aa..db54f18 100644
--- a/lib/rdf/blank_node/generator.ex
+++ b/lib/rdf/blank_node/generator.ex
@@ -55,10 +55,10 @@ defmodule RDF.BlankNode.Generator do
 
 
   @doc """
-  Generates a blank node for a given string according to the `RDF.BlankNode.Generator.Algorithm` set up.
+  Generates a blank node for a given value according to the `RDF.BlankNode.Generator.Algorithm` set up.
   """
-  def generate_for(pid, string) do
-    GenServer.call(pid, {:generate_for, string})
+  def generate_for(pid, value) do
+    GenServer.call(pid, {:generate_for, value})
   end
 
 
diff --git a/lib/rdf/blank_node/generator_algorithm.ex b/lib/rdf/blank_node/generator_algorithm.ex
index 423b305..a03802d 100644
--- a/lib/rdf/blank_node/generator_algorithm.ex
+++ b/lib/rdf/blank_node/generator_algorithm.ex
@@ -27,6 +27,6 @@ defmodule RDF.BlankNode.Generator.Algorithm do
   given state and return a tuple consisting of the generated blank node and the
   new state.
   """
-  @callback generate_for(string :: binary, state :: map) :: {RDF.BlankNode.t, map}
+  @callback generate_for(value :: any, state :: map) :: {RDF.BlankNode.t, map}
 
 end
diff --git a/lib/rdf/blank_node/increment.ex b/lib/rdf/blank_node/increment.ex
index c436f36..b252229 100644
--- a/lib/rdf/blank_node/increment.ex
+++ b/lib/rdf/blank_node/increment.ex
@@ -36,11 +36,11 @@ defmodule RDF.BlankNode.Increment do
   end
 
   @impl BlankNode.Generator.Algorithm
-  def generate_for(string, %{map: map, counter: counter} = state) do
-    case Map.get(map, string) do
+  def generate_for(value, %{map: map, counter: counter} = state) do
+    case Map.get(map, value) do
       nil ->
         {bnode(counter, state),
-          %{state | map: Map.put(map, string, counter), counter: counter + 1}}
+          %{state | map: Map.put(map, value, counter), counter: counter + 1}}
       previous ->
         {bnode(previous, state), state}
     end
diff --git a/test/unit/blank_node/increment_test.exs b/test/unit/blank_node/increment_test.exs
index 1b82e97..df45ddf 100644
--- a/test/unit/blank_node/increment_test.exs
+++ b/test/unit/blank_node/increment_test.exs
@@ -65,4 +65,18 @@ defmodule RDF.BlankNode.IncrementTest do
     assert Generator.generate_for(generator, "foo") == bnode("b2")
     assert Generator.generate(generator) == bnode("b6")
   end
+
+  test "generator with non-string values" do
+    {:ok, generator} = Generator.start_link(Increment, prefix: "b", hash: true)
+
+    assert Generator.generate(generator) == bnode("b0")
+    assert Generator.generate(generator) == bnode("b1")
+    assert Generator.generate_for(generator, {:foo, 42}) == bnode("b2")
+    assert Generator.generate(generator) == bnode("b3")
+    assert Generator.generate_for(generator, [:bar, 3.14]) == bnode("b4")
+    assert Generator.generate(generator) == bnode("b5")
+    assert Generator.generate_for(generator, {:foo, 42}) == bnode("b2")
+    assert Generator.generate(generator) == bnode("b6")
+  end
+
 end