diff --git a/lib/microformats2.rb b/lib/microformats2.rb
index 8515004..4359ecb 100644
--- a/lib/microformats2.rb
+++ b/lib/microformats2.rb
@@ -4,6 +4,7 @@ require "json"
 require "active_support/inflector"
 
 require "microformats2/version"
+require "microformats2/absolute_uri"
 require "microformats2/parser"
 require "microformats2/format_parser"
 require "microformats2/property_parser"
diff --git a/lib/microformats2/absolute_uri.rb b/lib/microformats2/absolute_uri.rb
new file mode 100644
index 0000000..a28e0d0
--- /dev/null
+++ b/lib/microformats2/absolute_uri.rb
@@ -0,0 +1,26 @@
+module Microformats2
+  class AbsoluteUri
+    attr_accessor :base, :relative
+
+    def initialize(base, relative)
+      @base = base
+      @relative = relative
+    end
+
+    def absolutize
+      return nil if relative.nil? or relative == ""
+
+      uri = URI.parse(relative)
+
+      if base && !uri.absolute?
+        uri = URI.join(base.to_s, relative.to_s)
+      end
+
+      uri.normalize!
+      uri.to_s
+
+    rescue URI::BadURIError, URI::InvalidURIError => e
+      relative.to_s
+    end
+  end
+end
diff --git a/lib/microformats2/collection.rb b/lib/microformats2/collection.rb
index 8469ecc..5ed43e0 100644
--- a/lib/microformats2/collection.rb
+++ b/lib/microformats2/collection.rb
@@ -88,7 +88,7 @@ module Microformats2
 
         if rel_values.member?("alternate")
           alternate_inst = {}
-          alternate_inst["url"] = absolutize(rel.attribute("href").text)
+          alternate_inst["url"] = Microformats2::AbsoluteUri.new(@base, rel.attribute("href").text).absolutize
           alternate_inst["rel"] = (rel_values - ["alternate"]).join(" ")
           unless rel.attribute("media").nil?
             alternate_inst["media"] = rel.attribute("media").text
@@ -103,21 +103,10 @@ module Microformats2
         else
           rel_values.each do |rel_value|
             @rels[rel_value] = [] unless @rels.has_key?(rel_value)
-            @rels[rel_value] << absolutize(rel.attribute("href").text)
+            @rels[rel_value] << Microformats2::AbsoluteUri.new(@base, rel.attribute("href").text).absolutize
           end
         end
       end
     end
-
-    def absolutize(href)
-      uri = URI.parse(href)
-
-      if @base && !uri.absolute?
-        uri = URI.join(@base, href)
-      end
-
-      uri.normalize!
-      uri.to_s
-    end
   end
 end
diff --git a/lib/microformats2/implied_property/url.rb b/lib/microformats2/implied_property/url.rb
index 54ae407..26e0ea3 100644
--- a/lib/microformats2/implied_property/url.rb
+++ b/lib/microformats2/implied_property/url.rb
@@ -7,19 +7,7 @@ module Microformats2
       end
 
       def to_s
-        @to_s = absolutize(super.to_s) if super.to_s != ""
-      end
-
-      # TODO: make dry, repeated in Collection
-      def absolutize(href)
-        uri = URI.parse(href)
-
-        if @base && !uri.absolute?
-          uri = URI.join(@base, href)
-        end
-
-        uri.normalize!
-        uri.to_s
+        @to_s = Microformats2::AbsoluteUri.new(@base, super.to_s).absolutize
       end
 
       protected
diff --git a/lib/microformats2/property/url.rb b/lib/microformats2/property/url.rb
index 85847a6..c86c6b6 100644
--- a/lib/microformats2/property/url.rb
+++ b/lib/microformats2/property/url.rb
@@ -3,19 +3,7 @@ module Microformats2
     class Url < Foundation
 
       def to_s
-        @to_s = absolutize(super.to_s)
-      end
-
-      # TODO: make dry, repeated in Collection
-      def absolutize(href)
-        uri = URI.parse(href)
-
-        if @base && !uri.absolute?
-          uri = URI.join(@base, href)
-        end
-
-        uri.normalize!
-        uri.to_s
+        @to_s = Microformats2::AbsoluteUri.new(@base, super.to_s).absolutize
       end
 
       protected
diff --git a/spec/lib/microformats2/absolute_uri_spec.rb b/spec/lib/microformats2/absolute_uri_spec.rb
new file mode 100644
index 0000000..56b4ee5
--- /dev/null
+++ b/spec/lib/microformats2/absolute_uri_spec.rb
@@ -0,0 +1,48 @@
+require "spec_helper"
+require "microformats2/absolute_uri"
+
+describe Microformats2::AbsoluteUri do
+  describe "#absolutize" do
+    subject { Microformats2::AbsoluteUri.new(base, relative).absolutize }
+    let(:base) { nil }
+
+    context "when relative is nil" do
+      let(:relative) { nil }
+      it { should be_nil }
+    end
+
+    context "when relative is an empty string" do
+      let(:relative) { "" }
+      it { should be_nil }
+    end
+
+    context "when relative is a valid absolute URI" do
+      let(:relative) { "http://google.com" }
+      it { should eq("http://google.com/") }
+    end
+
+    context "when relative is a valid non-absolute URI" do
+      let(:relative) { "bar/qux" }
+
+      context "and base is present but not absolute" do
+        let(:base) { "foo" }
+        it { should eq("bar/qux") }
+      end
+
+      context "and base is present and absolute" do
+        let(:base) { "http://google.com" }
+        it { should eq("http://google.com/bar/qux") }
+      end
+
+      context "and base is not present" do
+        let(:base) { nil }
+        it { should eq("bar/qux") }
+      end
+    end
+
+    context "when relative is an invalid URI" do
+      let(:relative) { "git@github.com:G5/microformats2.git" }
+      it { should eq("git@github.com:G5/microformats2.git") }
+    end
+  end
+end