diff --git a/pkgs/development/ruby-modules/gem-config/default.nix b/pkgs/development/ruby-modules/gem-config/default.nix
index d9ece64caedd6a..8c6ee465b01c2f 100644
--- a/pkgs/development/ruby-modules/gem-config/default.nix
+++ b/pkgs/development/ruby-modules/gem-config/default.nix
@@ -25,7 +25,7 @@
 , cairo, re2, rake, gobject-introspection, gdk-pixbuf, zeromq, czmq, graphicsmagick, libcxx
 , file, libvirt, glib, vips, taglib, libopus, linux-pam, libidn, protobuf, fribidi, harfbuzz
 , bison, flex, pango, python3, patchelf, binutils, freetds, wrapGAppsHook, atk
-, bundler, libsass, libselinux ? null, libsepol ? null
+, bundler, libsass, libselinux ? null, libsepol ? null, shared-mime-info
 }@args:
 
 let
@@ -379,6 +379,10 @@ in
     '';
   };
 
+  mimemagic = attrs: {
+    FREEDESKTOP_MIME_TYPES_PATH="${shared-mime-info}/share/mime/packages/freedesktop.org.xml";
+  };
+
   msgpack = attrs: {
     buildInputs = [ msgpack ];
   };