diff --git a/app/controllers/catalog_controller.rb b/app/controllers/catalog_controller.rb
index 3406bf00..46a7af66 100644
--- a/app/controllers/catalog_controller.rb
+++ b/app/controllers/catalog_controller.rb
@@ -95,7 +95,7 @@ def self.modified_field
     config.add_show_field solr_name('resource_type', :stored_searchable), label: 'Resource Type'
     config.add_show_field solr_name('format', :stored_searchable)
     config.add_show_field solr_name('identifier', :stored_searchable)
-    config.add_show_field 'ark_ssm', label: 'ARK'
+    config.add_show_field 'ark_ssi', label: 'ARK'
 
     config.add_show_field solr_name('caption', :stored_searchable)
     config.add_show_field solr_name('dimensions', :stored_searchable)
@@ -129,7 +129,7 @@ def self.modified_field
     # solr request handler? The one set in config[:default_solr_parameters][:qt],
     # since we aren't specifying it otherwise.
     config.add_search_field('all_fields', label: 'All Fields') do |field|
-      search_fields = 'title_tesim subject_tesim named_subject_tesim location_tesim description_tesim caption_tesim identifier_tesim local_identifier_sim ark_sim normalized_date_tesim photographer_tesim'
+      search_fields = 'title_tesim subject_tesim named_subject_tesim location_tesim description_tesim caption_tesim identifier_tesim local_identifier_sim ark_ssi normalized_date_tesim photographer_tesim'
 
       field.solr_parameters = {
         qf: search_fields,
diff --git a/app/importers/actor_record_importer.rb b/app/importers/actor_record_importer.rb
index 3ee8de59..d907e630 100644
--- a/app/importers/actor_record_importer.rb
+++ b/app/importers/actor_record_importer.rb
@@ -28,7 +28,7 @@ def find_existing_record(record)
     return unless record.respond_to?(deduplication_field)
     return if record.mapper.send(deduplication_field).nil?
     return if record.mapper.send(deduplication_field).empty?
-    existing_records = import_type.where(ark_sim: record.mapper.send(deduplication_field).to_s)
+    existing_records = import_type.where(ark_ssi: record.mapper.send(deduplication_field).to_s)
     raise "More than one record matches deduplication_field #{deduplication_field} with value #{record.mapper.send(deduplication_field)}" if existing_records.count > 1
     existing_records&.first
   end
diff --git a/app/importers/californica_csv_cleaner.rb b/app/importers/californica_csv_cleaner.rb
index adbf76a0..544179d6 100644
--- a/app/importers/californica_csv_cleaner.rb
+++ b/app/importers/californica_csv_cleaner.rb
@@ -41,7 +41,7 @@ def clean
       Work.where(identifier: ark).each do |work|
         work&.destroy!
       end
-      Work.where(ark_sim: ark).each do |work|
+      Work.where(ark_ssi: ark).each do |work|
         work&.destroy!
       end
     end
diff --git a/app/lib/californica/id_generator.rb b/app/lib/californica/id_generator.rb
index 92e72eb0..e907bf71 100644
--- a/app/lib/californica/id_generator.rb
+++ b/app/lib/californica/id_generator.rb
@@ -3,10 +3,15 @@ module Californica
   module IdGenerator
     # Take an ark value and return a valid fedora identifier
     def self.id_from_ark(ark)
-      split = ark.split('/')
-      shoulder = split[-2]
-      blade = split[-1]
-      "#{blade}-#{shoulder}"
+      id = ark.gsub(/ark:?\/?/, '')
+      shoulder, blade, extension = id.split('/')
+
+      # didn't see {shoulder}/{blade} format ark
+      raise ArgumentError, 'Could not parse ARK shoulder and blade' if blade.nil?
+      # looks like an extended ark
+      raise ArgumentError, 'ARK appears to have too many segments or extensions' unless extension.nil?
+
+      "#{shoulder}-#{blade}".reverse
     end
   end
 end
diff --git a/app/models/collection.rb b/app/models/collection.rb
index c6a2f6e5..b62654fa 100644
--- a/app/models/collection.rb
+++ b/app/models/collection.rb
@@ -11,7 +11,7 @@ class Collection < ActiveFedora::Base
   # @param ark [String] The ARK
   # @return [Collection] The Collection with that ARK
   def self.find_by_ark(ark)
-    where(ark_sim: ark).limit(1).first
+    where(ark_ssi: ark).limit(1).first
   end
 
   # @param ark [String] The ARK
diff --git a/app/models/solr_document.rb b/app/models/solr_document.rb
index d14de961..009fad61 100644
--- a/app/models/solr_document.rb
+++ b/app/models/solr_document.rb
@@ -27,7 +27,7 @@ class SolrDocument
   use_extension(Hydra::ContentNegotiation)
 
   def ark
-    self[:ark_ssm]
+    self[:ark_ssi]
   end
 
   def extent
diff --git a/app/models/ucla_metadata.rb b/app/models/ucla_metadata.rb
index 2e183378..02aa42b4 100644
--- a/app/models/ucla_metadata.rb
+++ b/app/models/ucla_metadata.rb
@@ -4,7 +4,7 @@ module UclaMetadata
 
   included do
     property :ark, predicate: ::RDF::Vocab::DC11.identifier, multiple: false do |index|
-      index.as :displayable, :facetable
+      index.as :stored_sortable
     end
 
     property :extent, predicate: ::RDF::Vocab::DC11.format do |index|
diff --git a/spec/importers/californica_importer_spec.rb b/spec/importers/californica_importer_spec.rb
index f6064f6f..14fdd21f 100644
--- a/spec/importers/californica_importer_spec.rb
+++ b/spec/importers/californica_importer_spec.rb
@@ -50,7 +50,7 @@
       it 'creates a new collection with a modified ark as the id' do
         importer.import
         new_collection = Collection.first
-        expect(new_collection.id).to eq "zz00294nz8-21198"
+        expect(new_collection.id).to eq "8zn49200zz-89112"
       end
       it 'creates a new collection and adds the work to it' do
         expect(Collection.count).to eq 0
diff --git a/spec/indexers/collection_indexer_spec.rb b/spec/indexers/collection_indexer_spec.rb
index ba756ffc..5b107251 100644
--- a/spec/indexers/collection_indexer_spec.rb
+++ b/spec/indexers/collection_indexer_spec.rb
@@ -10,7 +10,7 @@
     let(:attributes) { { ark: 'ark:/123/456' } }
 
     it 'add the fields to the solr document' do
-      expect(solr_document['ark_sim']).to eq ['ark:/123/456']
+      expect(solr_document['ark_ssi']).to eq 'ark:/123/456'
     end
   end
 end
diff --git a/spec/indexers/work_indexer_spec.rb b/spec/indexers/work_indexer_spec.rb
index c6e32663..a79bb8cb 100644
--- a/spec/indexers/work_indexer_spec.rb
+++ b/spec/indexers/work_indexer_spec.rb
@@ -78,7 +78,7 @@
     let(:attributes) { { ark: 'ark:/123/456' } }
 
     it 'indexes as a single value "string"' do
-      expect(solr_document['ark_sim']).to eq ['ark:/123/456']
+      expect(solr_document['ark_ssi']).to eq 'ark:/123/456'
     end
   end
 
@@ -86,7 +86,7 @@
     let(:attributes) { { ark: 'ark:/123/456' } }
 
     it 'does not duplicate the "ark:/"' do
-      expect(solr_document['ark_sim']).to eq ['ark:/123/456']
+      expect(solr_document['ark_ssi']).to eq 'ark:/123/456'
     end
   end
 end
diff --git a/spec/lib/californica/id_generator_spec.rb b/spec/lib/californica/id_generator_spec.rb
index 79af9b86..d3903793 100644
--- a/spec/lib/californica/id_generator_spec.rb
+++ b/spec/lib/californica/id_generator_spec.rb
@@ -3,8 +3,31 @@
 
 RSpec.describe Californica::IdGenerator, :clean do
   let(:ark) { 'ark:/13030/t8dn9c0x' }
+  let(:extended_ark) { 'ark:/13030/t8dn9c0x/001' }
+  let(:old_school) { '13030/t8dn9c0x' }
+  let(:wonky_ark) { 'ark:13030/t8dn9c0x' }
+  let(:non_ark) { 'this is not an ark' }
+
   it 'makes a fedora id from an ark' do
     id = Californica::IdGenerator.id_from_ark(ark)
-    expect(id).to eq 't8dn9c0x-13030'
+    expect(id).to eq 'x0c9nd8t-03031'
+  end
+
+  it 'makes an id from arks without prefixes' do
+    id = Californica::IdGenerator.id_from_ark(old_school)
+    expect(id).to eq 'x0c9nd8t-03031'
+  end
+
+  it 'has relaxed rules about prefixes' do
+    id = Californica::IdGenerator.id_from_ark(wonky_ark)
+    expect(id).to eq 'x0c9nd8t-03031'
+  end
+
+  it 'raises an error for arks with extensions' do
+    expect { Californica::IdGenerator.id_from_ark(extended_ark) }.to raise_error(ArgumentError, /ARK/)
+  end
+
+  it 'raises an error for arks that do not have a shoulder & blade' do
+    expect { Californica::IdGenerator.id_from_ark(non_ark) }.to raise_error(ArgumentError, /ARK/)
   end
 end
diff --git a/spec/system/create_work_spec.rb b/spec/system/create_work_spec.rb
index cf1e7e91..524f0384 100644
--- a/spec/system/create_work_spec.rb
+++ b/spec/system/create_work_spec.rb
@@ -56,7 +56,7 @@
       expect(page).to have_content("ark:/abc/123")
       expect(page).to have_content("Your files are being processed")
       work = Work.last
-      expect(work.id).to eq '123-abc'
+      expect(work.id).to eq '321-cba'
     end
   end
 end
diff --git a/spec/system/import_and_show_work_spec.rb b/spec/system/import_and_show_work_spec.rb
index fb85652a..57f57950 100644
--- a/spec/system/import_and_show_work_spec.rb
+++ b/spec/system/import_and_show_work_spec.rb
@@ -47,7 +47,7 @@
     it "displays expected fields on show work page" do
       importer.import
       work = Work.last
-      expect(work.id).to eq "hb338nb26f-13030"
+      expect(work.id).to eq "f62bn833bh-03031"
       visit("/concern/works/#{work.id}")
       expect(page).to have_content "Communion at Plaza Church, Los Angeles, 1942-1952" # title
       expect(page).to have_content "ark:/13030/hb338nb26f" # ark
diff --git a/spec/system/new_collection_spec.rb b/spec/system/new_collection_spec.rb
index 33679e00..a49a67f3 100644
--- a/spec/system/new_collection_spec.rb
+++ b/spec/system/new_collection_spec.rb
@@ -30,7 +30,7 @@
       expect(find_field('Ark').value).to eq ark
       expect(page).to have_content 'Collection was successfully created.'
       collection = Collection.last
-      expect(collection.id).to eq '1234-abc'
+      expect(collection.id).to eq '4321-cba'
     end
   end
 end