diff --git a/include/extern.h b/include/extern.h
index 59e84ba66..9cbc33bf2 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -658,7 +658,7 @@ extern int thitmonst(struct monst *, struct obj *);
 extern int hero_breaks(struct obj *, coordxy, coordxy, unsigned);
 extern int breaks(struct obj *, coordxy, coordxy);
 extern void release_camera_demon(struct obj *, coordxy, coordxy);
-extern void breakobj(struct obj *, coordxy, coordxy, boolean, boolean);
+extern int breakobj(struct obj *, coordxy, coordxy, boolean, boolean);
 extern boolean breaktest(struct obj *);
 extern boolean walk_path(coord *, coord *,
                          boolean(*)(void *, coordxy, coordxy), genericptr_t);
diff --git a/include/hack.h b/include/hack.h
index aadac06bb..e6fa6d4b7 100644
--- a/include/hack.h
+++ b/include/hack.h
@@ -303,7 +303,8 @@ enum cost_alteration_types {
     COST_BRKLCK  = 15, /* break box/chest's lock */
     COST_RUST    = 16, /* rust damage */
     COST_ROT     = 17, /* rotting attack */
-    COST_CORRODE = 18 /* acid damage */
+    COST_CORRODE = 18, /* acid damage */
+    COST_CRACK   = 19, /* damage to crystal armor */
 };
 
 /* read.c, create_particular() & create_particular_parse() */
diff --git a/include/obj.h b/include/obj.h
index fd5d0330a..f25f6ff13 100644
--- a/include/obj.h
+++ b/include/obj.h
@@ -436,6 +436,7 @@ struct obj {
 #define ERODE_RUST 1
 #define ERODE_ROT 2
 #define ERODE_CORRODE 3
+#define ERODE_CRACK 4 /* crystal armor */
 
 /* erosion flags for erode_obj() */
 #define EF_NONE 0
diff --git a/include/objclass.h b/include/objclass.h
index bfe5ae66e..309b19d47 100644
--- a/include/objclass.h
+++ b/include/objclass.h
@@ -192,6 +192,9 @@ extern NEARDATA struct objdescr obj_descr[NUM_OBJECTS + 1];
 /* primary damage: fire/rust/--- */
 /* is_flammable(otmp), is_rottable(otmp) in mkobj.c */
 #define is_rustprone(otmp) (objects[otmp->otyp].oc_material == IRON)
+#define is_crackable(otmp) \
+    (objects[(otmp)->otyp].oc_material == GLASS         \
+     && (otmp)->oclass == ARMOR_CLASS) /* erosion_matters() */
 /* secondary damage: rot/acid/acid */
 #define is_corrodeable(otmp) \
     (objects[otmp->otyp].oc_material == COPPER          \
@@ -199,6 +202,7 @@ extern NEARDATA struct objdescr obj_descr[NUM_OBJECTS + 1];
 /* subject to any damage */
 #define is_damageable(otmp) \
     (is_rustprone(otmp) || is_flammable(otmp)           \
-     || is_rottable(otmp) || is_corrodeable(otmp))
+     || is_rottable(otmp) || is_corrodeable(otmp)       \
+     || is_crackable(otmp))
 
 #endif /* OBJCLASS_H */
diff --git a/src/dothrow.c b/src/dothrow.c
index 831a1b0a7..83faea149 100644
--- a/src/dothrow.c
+++ b/src/dothrow.c
@@ -1273,8 +1273,7 @@ toss_up(struct obj *obj, boolean hitsroof)
         if (breaktest(obj)) {
             pline("%s hits the %s.", Doname2(obj), ceiling(u.ux, u.uy));
             breakmsg(obj, !Blind);
-            breakobj(obj, u.ux, u.uy, TRUE, TRUE);
-            return FALSE;
+            return breakobj(obj, u.ux, u.uy, TRUE, TRUE) ? FALSE : TRUE;
         }
         action = "hits";
     } else {
@@ -1297,8 +1296,9 @@ toss_up(struct obj *obj, boolean hitsroof)
                        ? rnd(25)
                        : 0;
         breakmsg(obj, !Blind);
-        breakobj(obj, u.ux, u.uy, TRUE, TRUE);
-        obj = 0; /* it's now gone */
+        if (breakobj(obj, u.ux, u.uy, TRUE, TRUE))
+            obj = 0; /* it's now gone */
+
         switch (otyp) {
         case EGG:
             if (petrifier && !Stone_resistance
@@ -1326,7 +1326,11 @@ toss_up(struct obj *obj, boolean hitsroof)
         default:
             break;
         }
-        return FALSE;
+        if (!obj)
+            return FALSE;
+        /* 'obj' still exists, so drop it and return True */
+        hitfloor(obj, FALSE);
+        gt.thrownobj = 0;
     } else if (harmless_missile(obj)) {
         pline("It doesn't hurt.");
         hitfloor(obj, FALSE);
@@ -1739,9 +1743,10 @@ throwit(struct obj *obj,
             nh_delay_output();
             tmp_at(DISP_END, 0);
             breakmsg(obj, cansee(gb.bhitpos.x, gb.bhitpos.y));
-            breakobj(obj, gb.bhitpos.x, gb.bhitpos.y, TRUE, TRUE);
-            clear_thrownobj = TRUE;
-            goto throwit_return;
+            if (breakobj(obj, gb.bhitpos.x, gb.bhitpos.y, TRUE, TRUE)) {
+                clear_thrownobj = TRUE;
+                goto throwit_return;
+            }
         }
         if (!Deaf && !Underwater) {
             /* Some sound effects when item lands in water or lava */
@@ -2334,9 +2339,10 @@ gem_accept(register struct monst *mon, register struct obj *obj)
  * Return 0 if the object didn't break, 1 if the object broke.
  */
 int
-hero_breaks(struct obj *obj,
-            coordxy x, coordxy y, /* object location (ox, oy may not be right) */
-            unsigned breakflags)
+hero_breaks(
+    struct obj *obj,
+    coordxy x, coordxy y, /* object location (ox, oy may not be right) */
+    unsigned breakflags)
 {
     /* from_invent: thrown or dropped by player; maybe on shop bill;
        by-hero is implicit so callers don't need to specify BRK_BY_HERO */
@@ -2351,8 +2357,7 @@ hero_breaks(struct obj *obj,
         return 0;
 
     breakmsg(obj, in_view);
-    breakobj(obj, x, y, TRUE, from_invent);
-    return 1;
+    return breakobj(obj, x, y, TRUE, from_invent);
 }
 
 /*
@@ -2361,16 +2366,16 @@ hero_breaks(struct obj *obj,
  * Return 0 if the object doesn't break, 1 if the object broke.
  */
 int
-breaks(struct obj *obj,
-       coordxy x, coordxy y) /* object location (ox, oy may not be right) */
+breaks(
+    struct obj *obj,
+    coordxy x, coordxy y) /* object location (ox, oy may not be right) */
 {
     boolean in_view = Blind ? FALSE : cansee(x, y);
 
     if (!breaktest(obj))
         return 0;
     breakmsg(obj, in_view);
-    breakobj(obj, x, y, FALSE, FALSE);
-    return 1;
+    return breakobj(obj, x, y, FALSE, FALSE);
 }
 
 void
@@ -2390,18 +2395,25 @@ release_camera_demon(struct obj *obj, coordxy x, coordxy y)
 }
 
 /*
- * Unconditionally break an object. Assumes all resistance checks
+ * Break an object.  Breakable armor goes through erosion steps; other
+ * items break unconditionally.  Assumes all resistance checks
  * and break messages have been delivered prior to getting here.
+ * (No longer true; breakmsg() is silent for crackable armor and we
+ * call erode_obj() for it and that delivers a damaged-the-item message.)
  */
-void
+int
 breakobj(
     struct obj *obj,
-    coordxy x, coordxy y,    /* object location (ox, oy may not be right) */
-    boolean hero_caused, /* is this the hero's fault? */
+    coordxy x, coordxy y,   /* object location (ox, oy may not be right) */
+    boolean hero_caused,    /* is this the hero's fault? */
     boolean from_invent)
 {
     boolean fracture = FALSE;
 
+    if (is_crackable(obj)) /* if erodeproof, erode_obj() will say so */
+        return (erode_obj(obj, armor_simple_name(obj), ERODE_CRACK,
+                          EF_DESTROY | EF_VERBOSE) == ER_DESTROYED);
+
     switch (obj->oclass == POTION_CLASS ? POT_WATER : obj->otyp) {
     case MIRROR:
         if (hero_caused)
@@ -2478,6 +2490,7 @@ breakobj(
     }
     if (!fracture)
         delobj(obj);
+    return 1;
 }
 
 /*
@@ -2490,15 +2503,16 @@ breaktest(struct obj *obj)
     int nonbreakchance = 1; /* chance for non-artifacts to resist */
 
     /* this may need to be changed if actual glass armor gets added someday;
-       for now, it affects crystal plate mail and helm of brilliance */
-    if (obj->oclass == ARMOR_CLASS)
-        nonbreakchance = 95;
+       for now, it affects crystal plate mail and helm of brilliance;
+       either of them will have to be cracked 4 times before breaking */
+    if (obj->oclass == ARMOR_CLASS && objects[obj->otyp].oc_material == GLASS)
+        nonbreakchance = 90;
 
     if (obj_resists(obj, nonbreakchance, 99))
-        return 0;
+        return FALSE;
     if (objects[obj->otyp].oc_material == GLASS && !obj->oartifact
         && obj->oclass != GEM_CLASS)
-        return 1;
+        return TRUE;
     switch (obj->oclass == POTION_CLASS ? POT_WATER : obj->otyp) {
     case EXPENSIVE_CAMERA:
     case POT_WATER: /* really, all potions */
@@ -2507,9 +2521,9 @@ breaktest(struct obj *obj)
     case MELON:
     case ACID_VENOM:
     case BLINDING_VENOM:
-        return 1;
+        return TRUE;
     default:
-        return 0;
+        return FALSE;
     }
 }
 
@@ -2518,14 +2532,15 @@ breakmsg(struct obj *obj, boolean in_view)
 {
     const char *to_pieces;
 
+    if (is_crackable(obj)) /* breakobj() will call erode_obj() for message */
+        return;
+
     to_pieces = "";
     switch (obj->oclass == POTION_CLASS ? POT_WATER : obj->otyp) {
     default: /* glass or crystal wand */
         if (obj->oclass != WAND_CLASS)
             impossible("breaking odd object (%d)?", obj->otyp);
         /*FALLTHRU*/
-    case CRYSTAL_PLATE_MAIL:
-    case HELM_OF_BRILLIANCE:
     case LENSES:
     case MIRROR:
     case CRYSTAL_BALL:
diff --git a/src/makemon.c b/src/makemon.c
index 3e0490e2a..59eac9516 100644
--- a/src/makemon.c
+++ b/src/makemon.c
@@ -2022,7 +2022,8 @@ mongets(register struct monst *mtmp, int otyp)
             otmp->cursed = FALSE;
             if (otmp->spe < 0)
                 otmp->spe = 0;
-            otmp->oerodeproof = TRUE;
+            otmp->oerodeproof = 1;
+            otmp->oeroded = otmp->oeroded2 = 0;
         } else if (is_mplayer(mtmp->data) && is_sword(otmp)) {
             otmp->spe = (3 + rn2(4));
         }
diff --git a/src/mkobj.c b/src/mkobj.c
index accd13eb3..b7b3baa45 100644
--- a/src/mkobj.c
+++ b/src/mkobj.c
@@ -201,7 +201,8 @@ mkobj_erosions(struct obj *otmp)
         if (!rn2(100)) {
             otmp->oerodeproof = 1;
         } else {
-            if (!rn2(80) && (is_flammable(otmp) || is_rustprone(otmp))) {
+            if (!rn2(80) && (is_flammable(otmp) || is_rustprone(otmp)
+                             || is_crackable(otmp))) {
                 do {
                     otmp->oeroded++;
                 } while (otmp->oeroded < 3 && !rn2(9));
@@ -729,7 +730,7 @@ bill_dummy_object(struct obj *otmp)
 static const char *const alteration_verbs[] = {
     "cancel", "drain", "uncharge", "unbless", "uncurse", "disenchant",
     "degrade", "dilute", "erase", "burn", "neutralize", "destroy", "splatter",
-    "bite", "open", "break the lock on", "rust", "rot", "tarnish"
+    "bite", "open", "break the lock on", "rust", "rot", "tarnish", "crack",
 };
 
 /* possibly bill for an object which the player has just modified */
diff --git a/src/objnam.c b/src/objnam.c
index 5b9212e67..979370ac5 100644
--- a/src/objnam.c
+++ b/src/objnam.c
@@ -1039,7 +1039,9 @@ add_erosion_words(struct obj* obj, char* prefix)
             Strcat(prefix, "thoroughly ");
             break;
         }
-        Strcat(prefix, is_rustprone(obj) ? "rusty " : "burnt ");
+        Strcat(prefix, is_rustprone(obj) ? "rusty "
+                       : is_crackable(obj) ? "cracked "
+                         : "burnt ");
     }
     if (obj->oeroded2 && !iscrys) {
         switch (obj->oeroded2) {
@@ -1052,21 +1054,21 @@ add_erosion_words(struct obj* obj, char* prefix)
         }
         Strcat(prefix, is_corrodeable(obj) ? "corroded " : "rotted ");
     }
+    /* note: it is possible for an item to be both eroded and erodeproof
+       (cursed scroll of destroy armor read while confused erodeproofs an
+       item of armor without repairing existing erosion) */
     if (rknown && obj->oerodeproof)
-        Strcat(prefix, iscrys
-                          ? "fixed "
-                          : is_rustprone(obj)
-                             ? "rustproof "
-                             : is_corrodeable(obj)
-                                ? "corrodeproof " /* "stainless"? */
-                                : is_flammable(obj)
-                                   ? "fireproof "
-                                   : "");
+        Strcat(prefix, iscrys ? "fixed "
+                       : is_rustprone(obj) ? "rustproof "
+                         : is_corrodeable(obj) ? "corrodeproof "
+                           : is_flammable(obj) ? "fireproof "
+                             : is_crackable(obj) ? "tempered " /* hardened */
+                               : "");
 }
 
 /* used to prevent rust on items where rust makes no difference */
 boolean
-erosion_matters(struct obj* obj)
+erosion_matters(struct obj *obj)
 {
     switch (obj->oclass) {
     case TOOL_CLASS:
@@ -1564,8 +1566,7 @@ not_fully_identified(struct obj* otmp)
             && otmp->oclass != BALL_CLASS)) /* (useless) */
         return FALSE;
     else /* lack of `rknown' only matters for vulnerable objects */
-        return (boolean) (is_rustprone(otmp) || is_corrodeable(otmp)
-                          || is_flammable(otmp));
+        return (boolean) is_damageable(otmp);
 }
 
 /* format a corpse name (xname() omits monster type; doname() calls us);
@@ -3617,7 +3618,9 @@ readobjnam_preparse(struct _readobjnam_data *d)
                    || !strncmpi(d->bp, "corrodeproof ", l = 13)
                    || !strncmpi(d->bp, "fixed ", l = 6)
                    || !strncmpi(d->bp, "fireproof ", l = 10)
-                   || !strncmpi(d->bp, "rotproof ", l = 9)) {
+                   || !strncmpi(d->bp, "rotproof ", l = 9)
+                   || !strncmpi(d->bp, "tempered ", l = 9)
+                   || !strncmpi(d->bp, "crackproof ", l = 11)) {
             d->erodeproof = 1;
         } else if (!strncmpi(d->bp, "lit ", l = 4)
                    || !strncmpi(d->bp, "burning ", l = 8)) {
@@ -3689,7 +3692,8 @@ readobjnam_preparse(struct _readobjnam_data *d)
         } else if (!strncmpi(d->bp, "rusty ", l = 6)
                    || !strncmpi(d->bp, "rusted ", l = 7)
                    || !strncmpi(d->bp, "burnt ", l = 6)
-                   || !strncmpi(d->bp, "burned ", l = 7)) {
+                   || !strncmpi(d->bp, "burned ", l = 7)
+                   || !strncmpi(d->bp, "cracked ", l = 8)) {
             d->eroded = 1 + d->very;
             d->very = 0;
         } else if (!strncmpi(d->bp, "corroded ", l = 9)
@@ -4846,7 +4850,8 @@ readobjnam(char *bp, struct obj *no_wish)
     if (erosion_matters(d.otmp)) {
         /* wished-for item shouldn't be eroded unless specified */
         d.otmp->oeroded = d.otmp->oeroded2 = 0;
-        if (d.eroded && (is_flammable(d.otmp) || is_rustprone(d.otmp)))
+        if (d.eroded && (is_flammable(d.otmp) || is_rustprone(d.otmp)
+                         || is_crackable(d.otmp)))
             d.otmp->oeroded = d.eroded;
         if (d.eroded2 && (is_corrodeable(d.otmp) || is_rottable(d.otmp)))
             d.otmp->oeroded2 = d.eroded2;
diff --git a/src/potion.c b/src/potion.c
index d18ed4430..296928717 100644
--- a/src/potion.c
+++ b/src/potion.c
@@ -2529,8 +2529,8 @@ potion_dip(struct obj *obj, struct obj *potion)
         } else if (obj->oclass != WEAPON_CLASS && !is_weptool(obj)) {
             /* the following cases apply only to weapons */
             goto more_dips;
-            /* Oil removes rust and corrosion, but doesn't unburn.
-             * Arrows, etc are classed as metallic due to arrowhead
+            /* Oil removes rust and corrosion, but doesn't unburn or repair
+             * cracks.  Arrows, etc are classed as metallic due to arrowhead
              * material, but dipping in oil shouldn't repair them.
              */
         } else if ((!is_rustprone(obj) && !is_corrodeable(obj))
diff --git a/src/trap.c b/src/trap.c
index e46694567..ec5175222 100644
--- a/src/trap.c
+++ b/src/trap.c
@@ -171,9 +171,10 @@ erode_obj(
     int ef_flags)
 {
     static NEARDATA const char
-        *const action[] = { "smoulder", "rust", "rot", "corrode" },
-        *const msg[] = { "burnt", "rusted", "rotten", "corroded" },
-        *const bythe[] = { "heat", "oxidation", "decay", "corrosion" };
+        *const action[] = { "smoulder", "rust", "rot", "corrode", "crack" },
+        *const msg[] = { "burnt", "rusted", "rotten", "corroded", "cracked" },
+        *const bythe[] = { "heat", "oxidation", "decay", "corrosion",
+                           "impact" }; /* this could use improvement... */
     boolean vulnerable = FALSE, is_primary = TRUE,
             check_grease = (ef_flags & EF_GREASE) ? TRUE : FALSE,
             print = (ef_flags & EF_VERBOSE) ? TRUE : FALSE,
@@ -219,6 +220,11 @@ erode_obj(
         is_primary = FALSE;
         cost_type = COST_CORRODE;
         break;
+    case ERODE_CRACK: /* crystal armor */
+        vulnerable = is_crackable(otmp);
+        is_primary = TRUE;
+        cost_type = COST_CRACK;
+        break;
     default:
         impossible("Invalid erosion type in erode_obj");
         return ER_NOTHING;
@@ -288,13 +294,19 @@ erode_obj(
         return ER_DAMAGED;
     } else if (ef_flags & EF_DESTROY) {
         otmp->in_use = 1; /* in case of hangup during message w/ --More-- */
-        if (uvictim || vismon || visobj)
-            pline("%s %s %s away!",
+        if (uvictim || vismon || visobj) {
+            char actbuf[BUFSZ];
+
+            if (cost_type != COST_CRACK)
+                Sprintf(actbuf, "%s away", vtense(ostr, action[type]));
+            else
+                Sprintf(actbuf, "shatters");
+            pline("%s %s %s!",
                   uvictim ? "Your"
                           : !vismon ? "The" /* visobj */
                                     : s_suffix(Monnam(victim)),
-                  ostr, vtense(ostr, action[type]));
-
+                  ostr, actbuf);
+        }
         if (ef_flags & EF_PAY)
             costly_alteration(otmp, cost_type);
 
diff --git a/src/zap.c b/src/zap.c
index 89fb322c4..69541ca36 100644
--- a/src/zap.c
+++ b/src/zap.c
@@ -1715,7 +1715,7 @@ poly_obj(struct obj *obj, int id)
     otmp->blessed = obj->blessed;
 
     if (erosion_matters(otmp)) {
-        if (is_flammable(otmp) || is_rustprone(otmp))
+        if (is_flammable(otmp) || is_rustprone(otmp) || is_crackable(otmp))
             otmp->oeroded = obj->oeroded;
         if (is_corrodeable(otmp) || is_rottable(otmp))
             otmp->oeroded2 = obj->oeroded2;
@@ -5144,7 +5144,9 @@ fracture_rock(struct obj *obj) /* no texts here! */
             /* shop message says "you owe <shk> <$> for it!" so we need
                to precede that with a message explaining what "it" is */
             You("fracture %s %s.", s_suffix(shkname(shkp)), xname(obj));
-            breakobj(obj, x, y, TRUE, FALSE); /* charges for shop goods */
+            /* breakobj won't destroy fracturing statue or boulder but
+               will charge for shop goods */
+            (void) breakobj(obj, x, y, TRUE, FALSE);
         }
     }
     if (by_you && obj->otyp == BOULDER)