diff --git a/app/models/hyrax/file_metadata.rb b/app/models/hyrax/file_metadata.rb
index 2d52b95eb6..d20c921d9e 100644
--- a/app/models/hyrax/file_metadata.rb
+++ b/app/models/hyrax/file_metadata.rb
@@ -13,12 +13,14 @@ module Use
       THUMBNAIL = ::Valkyrie::Vocab::PCDMUse.ThumbnailImage
 
       ##
-      # @param use [Symbol]
+      # @param use [RDF::URI, Symbol]
       #
       # @return [RDF::URI]
       # @raise [ArgumentError] if no use is known for the argument
       def uri_for(use:)
         case use
+        when RDF::URI
+          use
         when :original_file
           ORIGINAL_FILE
         when :extracted_file
diff --git a/app/services/hyrax/characterization/file_set_description.rb b/app/services/hyrax/characterization/file_set_description.rb
index dd310f5485..1ce747df2d 100644
--- a/app/services/hyrax/characterization/file_set_description.rb
+++ b/app/services/hyrax/characterization/file_set_description.rb
@@ -16,9 +16,9 @@ class FileSetDescription
 
       ##
       # @param [Hyrax::FileSet] file_set
-      # @param [Symbol] primary_file  a symbol mapping to the file_set member
-      #   used for characterization
-      def initialize(file_set:, primary_file: :original_file)
+      # @param [RDF::URI, Symbol] primary_file  the type of file_set member to
+      #   use for characterization
+      def initialize(file_set:, primary_file: Hyrax::FileMetadata::Use::ORIGINAL_FILE)
         self.file_set = file_set
 
         @primary_file_type_uri =
diff --git a/spec/services/hyrax/characterization/file_set_description_spec.rb b/spec/services/hyrax/characterization/file_set_description_spec.rb
index 0ef61ff3b0..be78d5cf4a 100644
--- a/spec/services/hyrax/characterization/file_set_description_spec.rb
+++ b/spec/services/hyrax/characterization/file_set_description_spec.rb
@@ -7,6 +7,7 @@
   let(:file) { Rack::Test::UploadedFile.new('spec/fixtures/world.png', ctype) }
   let(:file_set) { FactoryBot.valkyrie_create(:hyrax_file_set, file_ids: file_ids) }
   let(:file_ids) { [] }
+  let(:original_file) { Hyrax.persister.save(resource: Hyrax::FileMetadata.for(file: file)) }
 
   describe '#mime_type' do
     context 'before the file set is saved' do
@@ -25,7 +26,6 @@
 
     context 'when it has an original file' do
       let(:file_ids) { [original_file.id] }
-      let(:original_file) { Hyrax.persister.save(resource: Hyrax::FileMetadata.for(file: file)) }
 
       it { is_expected.to be_image }
 
@@ -33,5 +33,24 @@
         expect(description.mime_type).to eq ctype
       end
     end
+
+    context 'when it uses a custom URI type' do
+      subject(:description) { described_class.new(file_set: file_set, primary_file: custom_type) }
+      let(:file_ids) { [custom_file.id, original_file.id] }
+      let(:custom_type) { RDF::URI('http://example.com/HyraxTestCustomType') }
+      let(:other_ctype) { 'image/jpg' }
+      let(:other_file) { Rack::Test::UploadedFile.new('spec/fixtures/1.5mb-avatar.jpg', other_ctype) }
+
+      let(:custom_file) do
+        resource = Hyrax::FileMetadata.for(file: other_file).new(type: custom_type)
+        Hyrax.persister.save(resource: resource)
+      end
+
+      it { is_expected.to be_image }
+
+      it 'has a mime type from a file' do
+        expect(description.mime_type).to eq other_ctype
+      end
+    end
   end
 end