diff --git a/setup.py b/setup.py
index 497b5ac..284795d 100644
--- a/setup.py
+++ b/setup.py
@@ -55,7 +55,7 @@ except:
     pil_include = []
 
 # used to figure out what files to compile
-render_modes = ['normal', 'overlay', 'lighting', 'night', 'spawn', 'cave']
+render_modes = ['normal', 'overlay', 'lighting', 'night', 'spawn', 'cave', 'mineral']
 
 c_overviewer_files = ['src/main.c', 'src/composite.c', 'src/iterate.c', 'src/endian.c', 'src/rendermodes.c']
 c_overviewer_files += map(lambda mode: 'src/rendermode-%s.c' % (mode,), render_modes)
diff --git a/src/overviewer.h b/src/overviewer.h
index 55243a5..05f657c 100644
--- a/src/overviewer.h
+++ b/src/overviewer.h
@@ -26,7 +26,7 @@
 
 // increment this value if you've made a change to the c extesion
 // and want to force users to rebuild
-#define OVERVIEWER_EXTENSION_VERSION 5
+#define OVERVIEWER_EXTENSION_VERSION 6
 
 /* Python PIL, and numpy headers */
 #include <Python.h>
diff --git a/src/rendermode-mineral.c b/src/rendermode-mineral.c
new file mode 100644
index 0000000..a45bbf2
--- /dev/null
+++ b/src/rendermode-mineral.c
@@ -0,0 +1,104 @@
+/*
+ * This file is part of the Minecraft Overviewer.
+ *
+ * Minecraft Overviewer is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * Minecraft Overviewer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with the Overviewer.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "overviewer.h"
+
+struct OreColor {
+    unsigned char blockid;
+    unsigned char r, g, b, a;
+};
+
+/* put more valuable ores first -- they take precedence */
+static struct OreColor orecolors[] = {
+    {56 /* Diamond Ore */, 32, 230, 220, 200},
+    
+    /* end of list marker */
+    {0, 0, 0, 0, 0}
+};
+
+static void get_color(void *data, RenderState *state,
+                      unsigned char *r, unsigned char *g, unsigned char *b, unsigned char *a) {
+    
+    int x = state->x, y = state->y, z_max = state->z, z;
+    //RenderModeMineral* self = (RenderModeMineral *)data;
+    *a = 0;
+    
+    for (z = 0; z <= z_max; z++) {
+        int i, max_i = sizeof(orecolors) / sizeof(struct OreColor);
+        unsigned char blockid = getArrayByte3D(state->blocks, x, y, z);
+        
+        for (i = 0; i < max_i && orecolors[i].blockid != 0; i++) {
+            if (orecolors[i].blockid == blockid) {
+                *r = orecolors[i].r;
+                *g = orecolors[i].g;
+                *b = orecolors[i].b;
+                *a = orecolors[i].a;
+                max_i = i;
+                break;
+            }
+        }
+    }
+}
+
+static int
+rendermode_mineral_start(void *data, RenderState *state) {
+    RenderModeMineral* self;
+
+    /* first, chain up */
+    int ret = rendermode_overlay.start(data, state);
+    if (ret != 0)
+        return ret;
+    
+    /* now do custom initializations */
+    self = (RenderModeMineral *)data;
+    
+    /* setup custom color */
+    self->parent.get_color = get_color;
+    
+    return 0;
+}
+
+static void
+rendermode_mineral_finish(void *data, RenderState *state) {
+    /* first free all *our* stuff */
+    //RenderModeMineral* self = (RenderModeMineral *)data;
+    
+    /* now, chain up */
+    rendermode_overlay.finish(data, state);
+}
+
+static int
+rendermode_mineral_occluded(void *data, RenderState *state) {
+    /* no special occlusion here */
+    return rendermode_overlay.occluded(data, state);
+}
+
+static void
+rendermode_mineral_draw(void *data, RenderState *state, PyObject *src, PyObject *mask) {
+    /* draw normally */
+    rendermode_overlay.draw(data, state, src, mask);
+}
+
+RenderModeInterface rendermode_mineral = {
+    "mineral", "draws a colored overlay showing where ores are located",
+    &rendermode_overlay,
+    sizeof(RenderModeMineral),
+    rendermode_mineral_start,
+    rendermode_mineral_finish,
+    rendermode_mineral_occluded,
+    rendermode_mineral_draw,
+};
diff --git a/src/rendermodes.c b/src/rendermodes.c
index 43658e1..2d1f8d1 100644
--- a/src/rendermodes.c
+++ b/src/rendermodes.c
@@ -27,6 +27,7 @@ static RenderModeInterface *render_modes[] = {
     &rendermode_night,
     &rendermode_spawn,
     &rendermode_cave,
+    &rendermode_mineral,
     NULL
 };
 
diff --git a/src/rendermodes.h b/src/rendermodes.h
index fd0b479..9e731b1 100644
--- a/src/rendermodes.h
+++ b/src/rendermodes.h
@@ -156,4 +156,11 @@ typedef struct {
 } RenderModeCave;
 extern RenderModeInterface rendermode_cave;
 
+/* MINERAL */
+typedef struct {
+    /* inherits from overlay */
+    RenderModeOverlay parent;
+} RenderModeMineral;
+extern RenderModeInterface rendermode_mineral;
+
 #endif /* __RENDERMODES_H_INCLUDED__ */