decimal.diff

diff --git a/lib/wax_helpers.m b/lib/wax_helpers.m
index dee91a9..f0c351d 100644
--- a/lib/wax_helpers.m
+++ b/lib/wax_helpers.m
@@ -219,7 +219,7 @@ void wax_fromInstance(lua_State *L, id instance) {
         if ([instance isKindOfClass:[NSString class]]) {    
             lua_pushstring(L, [(NSString *)instance UTF8String]);
         }
-        else if ([instance isKindOfClass:[NSNumber class]]) {
+        else if ([instance isKindOfClass:[NSNumber class]] && ![instance isKindOfClass:[NSDecimalNumber class]])              lua_pushnumber(L, [instance doubleValue]);
         }
         else if ([instance isKindOfClass:[NSArray class]]) {