diff --git a/rdf.gemspec b/rdf.gemspec
index 401e3a81..91db71c7 100755
--- a/rdf.gemspec
+++ b/rdf.gemspec
@@ -31,6 +31,8 @@ Gem::Specification.new do |gem|
   gem.requirements               = []
   gem.add_runtime_dependency     'link_header', '~> 0.0', '>= 0.0.8'
   gem.add_runtime_dependency     'bcp47_spec',  '~> 0.2'
+  gem.add_runtime_dependency     'bigdecimal',  '~> 3.1', '>= 3.1.5'
+  gem.add_development_dependency 'base64',      '~> 0.2'
   gem.add_development_dependency 'rdf-spec',    '~> 3.3'
   gem.add_development_dependency 'rdf-turtle',  '~> 3.3'
   gem.add_development_dependency 'rdf-vocab',   '~> 3.3'