diff --git a/burnman/calibrants/Fei_2007.py b/burnman/calibrants/Fei_2007.py
index 51572839..56e77bbb 100644
--- a/burnman/calibrants/Fei_2007.py
+++ b/burnman/calibrants/Fei_2007.py
@@ -33,22 +33,14 @@ def _pressure_Fei_Pt(volume, temperature, params):
             Pth0 = thermal_model._thermal_pressure(params["T_0"], volume, params)
             Pth = thermal_model._thermal_pressure(temperature, volume, params)
 
-            # Electronic pressure
-            Pel = (
-                1.1916e-15 * temperature**4.0
-                - 1.4551e-11 * temperature**3.0
-                + 1.6209e-07 * temperature**2.0
-                + 1.8269e-4 * temperature
-                - 0.069
-            ) * 1.0e09
-
             # Total pressure
-            P = P0 + Pth - Pth0 + Pel
+            P = P0 + Pth - Pth0
 
             return P
 
+        Z = 4.0
         _params_Fei_Pt = {
-            "V_0": 9.0904e-06,
+            "V_0": molar_volume_from_unit_cell_volume(60.38, Z),
             "K_0": 277.0e9,
             "Kprime_0": 5.08,
             "Debye_0": 230.0,
@@ -57,7 +49,7 @@ def _pressure_Fei_Pt(volume, temperature, params):
             "n": 1.0,
             "T_0": 300.0,
             "P_0": 0.0,
-            "Z": 4.0,
+            "Z": Z,
         }
 
         Calibrant.__init__(self, _pressure_Fei_Pt, "pressure", _params_Fei_Pt)
@@ -86,17 +78,18 @@ def _pressure_Fei_Au(volume, temperature, params):
 
             return P
 
+        Z = 4.0
         _params_Fei_Au = {
-            "V_0": molar_volume_from_unit_cell_volume(67.850, 4.0),
+            "V_0": molar_volume_from_unit_cell_volume(67.850, Z),
             "K_0": 167.0e9,
-            "Kprime_0": 6.00,
+            "Kprime_0": 6.0,
             "Debye_0": 170.0,
             "grueneisen_0": 2.97,
             "q_0": 0.6,
             "n": 1.0,
             "T_0": 300.0,
             "P_0": 0.0,
-            "Z": 4.0,
+            "Z": Z,
         }
 
         Calibrant.__init__(self, _pressure_Fei_Au, "pressure", _params_Fei_Au)
diff --git a/burnman/calibrants/Holmes_1989.py b/burnman/calibrants/Holmes_1989.py
index 7480e6aa..b0efb85f 100644
--- a/burnman/calibrants/Holmes_1989.py
+++ b/burnman/calibrants/Holmes_1989.py
@@ -32,12 +32,14 @@ def _pressure(volume, temperature, params):
 
             return P_300 + params["alpha_T"] * params["beta_T"] * (temperature - 300.0)
 
+        Z = 4.0
         _params = {
-            "V_0": molar_volume_from_unit_cell_volume(60.38, 4.0),
+            "V_0": molar_volume_from_unit_cell_volume(60.38, Z),
             "beta_T": 798.31e9 / 3.0,
             "eta": 7.2119,
             "beta_prime_T": (7.2119 / 1.5) + 1.0,
             "alpha_T": 2.61e-5,
+            "Z": Z,
         }
 
         Calibrant.__init__(self, _pressure, "pressure", _params)
diff --git a/misc/benchmarks/calibrant_benchmarks.py b/misc/benchmarks/calibrant_benchmarks.py
new file mode 100644
index 00000000..b64d0d6e
--- /dev/null
+++ b/misc/benchmarks/calibrant_benchmarks.py
@@ -0,0 +1,53 @@
+from __future__ import absolute_import
+
+import numpy as np
+import matplotlib.pyplot as plt
+import matplotlib.image as mpimg
+from burnman import calibrants
+from burnman.tools.unitcell import molar_volume_from_unit_cell_volume
+
+
+def make_VPT_figure(calibrant, temperatures, figure, figure_extent, plot_extent):
+    print(f"Checking {calibrant} Au...")
+
+    fig = plt.figure(figsize=(6, 4))
+    fig.suptitle(f"{calibrant}")
+
+    ax = [fig.add_subplot(1, 1, 1)]
+
+    fig1 = mpimg.imread(figure)
+    ax[0].imshow(fig1, extent=figure_extent, aspect="auto")
+
+    pressures = np.linspace(plot_extent[0], plot_extent[1], 101)
+    volumes = np.empty_like(pressures)
+    for T in [300., 1473., 2173.]:
+        for i, P in enumerate(pressures):
+            volumes[i] = (calibrant.volume(P, T) /
+                          molar_volume_from_unit_cell_volume(1., calibrant.params["Z"]))
+
+        plt.plot(pressures/1.e9, volumes)
+
+    ax[0].set_xlim(plot_extent[0], plot_extent[1])
+    ax[0].set_ylim(plot_extent[2], plot_extent[3])
+    plt.show()
+
+
+def check_figures():
+    make_VPT_figure(calibrants.Fei_2007.Au(),
+                    [300., 1473., 2173.],
+                    "figures/Fei_2007_Au.png",
+                    [0, 139.5, 50, 68], [0, 139.5, 50, 68])
+
+    make_VPT_figure(calibrants.Fei_2007.Pt(),
+                    [300., 1473., 1873.],
+                    "figures/Fei_2007_Pt.png",
+                    [-2, 125, 46.98, 61.02], [0, 125, 47, 61])
+
+    make_VPT_figure(calibrants.Holmes_1989.Pt(),
+                    [300.],
+                    "figures/Holmes_1989_Pt.png",
+                    [-2, 125, 46.98, 61.02], [0, 125, 47, 61])
+
+
+if __name__ == "__main__":
+    check_figures()