diff --git a/src/build123d/build_generic.py b/src/build123d/build_generic.py
index d6e442a..79b9819 100644
--- a/src/build123d/build_generic.py
+++ b/src/build123d/build_generic.py
@@ -26,8 +26,9 @@ license:
     limitations under the License.
 
 """
-from typing import Union
+import copy
 import logging
+from typing import Union
 from build123d.build_enums import Mode, Kind, Keep
 from build123d.direct_api import (
     Edge,
@@ -330,17 +331,7 @@ class Mirror(Compound):
         self.about = about
         self.mode = mode
 
-        scale_matrix = Matrix(
-            [
-                [1.0, 0.0, 00.0, 0.0],
-                [0.0, 1.0, 00.0, 0.0],
-                [0.0, 0.0, -1.0, 0.0],
-                [0.0, 0.0, 00.0, 1.0],
-            ]
-        )
-        localized = [about.to_local_coords(o) for o in objects]
-        local_mirrored = [o.transform_geometry(scale_matrix) for o in localized]
-        mirrored = [about.from_local_coords(o) for o in local_mirrored]
+        mirrored = [copy.deepcopy(o).mirror(about) for o in objects]
 
         context._add_to_context(*mirrored, mode=mode)
         super().__init__(Compound.make_compound(mirrored).wrapped)
diff --git a/tests/build_generic_tests.py b/tests/build_generic_tests.py
index 98a3405..5e7b339 100644
--- a/tests/build_generic_tests.py
+++ b/tests/build_generic_tests.py
@@ -216,7 +216,7 @@ class ChamferTests(unittest.TestCase):
                 Rectangle(10, 10)
             Chamfer(
                 *test.vertices().filter_by_position(Axis.X, minimum=0, maximum=20),
-                length=1
+                length=1,
             )
         self.assertAlmostEqual(test.sketch.area, 200 - 4 * 0.5, 5)
 
@@ -244,7 +244,7 @@ class FilletTests(unittest.TestCase):
                 Rectangle(10, 10)
             Fillet(
                 *test.vertices().filter_by_position(Axis.X, minimum=0, maximum=20),
-                radius=1
+                radius=1,
             )
         self.assertAlmostEqual(test.sketch.area, 200 - 4 + pi, 5)
 
@@ -323,6 +323,23 @@ class MirrorTests(unittest.TestCase):
             len(test.solids().filter_by_position(Axis.X, minimum=-10, maximum=0)), 1
         )
 
+    def test_changing_object_type(self):
+        """Using gp_GTrsf for the mirror operation may change the nature of the object"""
+        ring_r, ring_t = 9, 2
+        wheel_r, wheel_t = 10, 6
+
+        with BuildPart() as p:
+            with BuildSketch(Plane.XZ) as side:
+                Trapezoid(wheel_r, wheel_t / 2, 90, 45, centered=(False, False))
+                with Locations((ring_r, ring_t / 2)):
+                    Circle(ring_t / 2, centered=(True, True), mode=Mode.SUBTRACT)
+                with Locations((wheel_r, ring_t / 2)):
+                    Rectangle(2, 2, centered=(True, True), mode=Mode.SUBTRACT)
+            Revolve(axis=Axis.Z)
+            Mirror(about=Plane.XY)
+            construction_face = p.faces().sort_by(Axis.Z)[0]
+            self.assertEqual(construction_face.geom_type(), "PLANE")
+
 
 class ScaleTests(unittest.TestCase):
     def test_line(self):