1.7.2 sediment materials.

- Red sand equals sand. In most biome's, it's not going
  to get degraded further, but if deposited into an ocean or
  other wet biome, it'll turn into clay as normal.
- hardened clay and stained clay are considered as hard as
  stone (e.g. sandstone) in minecraft (see wiki). For that
  reason, we'll consider these equivalend to sandstone and
  cobblestone, so they degrade into gravel and are not
  very movable.

src/org/foo_projects/sofar/Sedimentology/Sedimentology.java

@@ -240,7 +240,7 @@ public final class Sedimentology extends JavaPlugin {
 			case DIRT:
 			case GRASS:
 				break;
-			case SAND:
+			case SAND: /* this covers red sand */
 				/*
 				 * breaking sand into clay is hard, this also prevents all
 				 * sand from turning into clay
@@ -254,10 +254,9 @@ public final class Sedimentology extends JavaPlugin {
 			case CLAY:
 				resistance = 0.3;
 				break;
+			case HARD_CLAY:
+			case STAINED_CLAY:
 			case SANDSTONE:
-				hardness = 0.05;
-				resistance = 0.05;
-				break;
 			case COBBLESTONE:
 				hardness = 0.05;
 				resistance = 0.05;
@@ -528,6 +527,8 @@ displace:
 						case GRAVEL:
 							snd = Sound.DIG_GRAVEL;
 							break;
+						case HARD_CLAY:
+						case STAINED_CLAY:
 						case COBBLESTONE:
 						case STONE:
 						case COAL_ORE:
@@ -618,6 +619,8 @@ displace:
 				case CLAY:
 					/* we can displace clay, but not degrade */
 					return;
+				case HARD_CLAY:
+				case STAINED_CLAY:
 				case SANDSTONE:
 				case COBBLESTONE:
 					b.setType(Material.GRAVEL);