diff --git a/src/simulation/Simulation.cpp b/src/simulation/Simulation.cpp
index 9f2d7bd78..51921421d 100644
--- a/src/simulation/Simulation.cpp
+++ b/src/simulation/Simulation.cpp
@@ -2382,9 +2382,8 @@ void Simulation::init_can_move()
 		can_move[movingType][PT_FIGH] = 0;
 		//INVS behaviour varies with pressure
 		can_move[movingType][PT_INVIS] = 3;
-		//stop CNCT and ROCK from being displaced by other particles
+		//stop CNCT from being displaced by other particles
 		can_move[movingType][PT_CNCT] = 0;
-		can_move[movingType][PT_ROCK] = 0;
 		//VOID and PVOD behaviour varies with powered state and ctype
 		can_move[movingType][PT_PVOD] = 3;
 		can_move[movingType][PT_VOID] = 3;
diff --git a/src/simulation/elements/FIRE.cpp b/src/simulation/elements/FIRE.cpp
index 8ff5fd6a3..77b2c9416 100644
--- a/src/simulation/elements/FIRE.cpp
+++ b/src/simulation/elements/FIRE.cpp
@@ -87,6 +87,56 @@ int Element_FIRE_update(UPDATE_FUNC_ARGS)
 			}
 		}
 		break;
+	case PT_LAVA:
+		if (parts[i].ctype == PT_ROCK)
+		{
+			float pres = sim->pv[y / CELL][x / CELL];
+			if (pres <= -9)
+			{
+				parts[i].ctype = PT_STNE;
+				break;
+			}
+
+			if (pres >= 25 && RNG::Ref().chance(1, 12500))
+			{
+				if (pres <= 50)
+				{
+					if (RNG::Ref().chance(1, 2))
+						parts[i].ctype = PT_BRMT;
+					else
+						parts[i].ctype = PT_CNCT;
+				}
+				else if (pres <= 75)
+				{
+					if (pres >= 73 || RNG::Ref().chance(1, 8))
+						parts[i].ctype = PT_GOLD;
+					else
+						parts[i].ctype = PT_QRTZ;
+				}
+				else if (pres <= 100 && parts[i].temp >= 5000)
+				{
+					if (RNG::Ref().chance(1, 5)) // 1 in 5 chance IRON to TTAN
+						parts[i].ctype = PT_TTAN;
+					else
+						parts[i].ctype = PT_IRON;
+				}
+				else if (pres <= 255 && parts[i].temp >= 5000 && RNG::Ref().chance(1, 5))
+				{
+					if (RNG::Ref().chance(1, 5))
+						parts[i].ctype = PT_URAN;
+					else if (RNG::Ref().chance(1, 5))
+						parts[i].ctype = PT_PLUT;
+					else
+						parts[i].ctype = PT_TUNG;
+				}
+			}
+		}
+		else if (parts[i].ctype == PT_STNE && sim->pv[y / CELL][x / CELL] >= 2.0f) // Form ROCK with pressure
+		{
+			parts[i].tmp2 = RNG::Ref().between(0, 10); // Provide tmp2 for color noise
+			parts[i].ctype = PT_ROCK;
+		}
+		break;
 	default:
 		break;
 	}
@@ -194,64 +244,12 @@ int Element_FIRE_update(UPDATE_FUNC_ARGS)
 							parts[ID(r)].ctype = PT_HEAC;
 						}
 					}
-					else if (parts[i].ctype == PT_ROCK)
+					else if (parts[i].ctype == PT_ROCK && rt == PT_LAVA && parts[ID(r)].ctype == PT_GOLD && parts[ID(r)].tmp == 0 &&
+						sim->pv[y / CELL][x / CELL] >= 50 && RNG::Ref().chance(1, 10000)) // Produce GOLD veins/clusters
 					{
-						float pres = sim->pv[y / CELL][x / CELL];
-						if (pres <= -9)
-						{
-							parts[i].ctype = PT_STNE;
-							break;
-						}
-
-						if (pres >= 25 && RNG::Ref().chance(1, 100000))
-						{
-							if (pres <= 50)
-							{
-								if (RNG::Ref().chance(1, 2))
-									parts[i].ctype = PT_BRMT;
-								else
-									parts[i].ctype = PT_CNCT;
-								break;
-							}
-							else if (pres <= 75)
-							{
-								if (pres >= 73 || RNG::Ref().chance(1, 8))
-									parts[i].ctype = PT_GOLD;
-								else
-									parts[i].ctype = PT_QRTZ;
-								break;
-							}
-							else if (pres <= 100 && parts[i].temp >= 5000)
-							{
-								if (RNG::Ref().chance(1, 5)) // 1 in 5 chance IRON to TTAN
-									parts[i].ctype = PT_TTAN;
-								else
-									parts[i].ctype = PT_IRON;
-								break;
-							}
-							else if (pres <= 255 && parts[i].temp >= 5000 && RNG::Ref().chance(1, 5))
-							{
-								if (RNG::Ref().chance(1, 5))
-									parts[i].ctype = PT_URAN;
-								else if (RNG::Ref().chance(1, 5))
-									parts[i].ctype = PT_PLUT;
-								else
-									parts[i].ctype = PT_TUNG;
-								break;
-							}
-						}
-
-						if (parts[ID(r)].ctype == PT_GOLD && parts[ID(r)].tmp == 0 && pres >= 50 && RNG::Ref().chance(1, 10000)) // Produce GOLD veins/clusters
-						{
-							parts[i].ctype = PT_GOLD;
-							if (rx > 1 || rx < -1) // Trend veins vertical
-								parts[i].tmp = 1;
-						}
-					}
-					else if (parts[i].ctype == PT_STNE && sim->pv[y / CELL][x / CELL] >= 2.0f) // Form ROCK with pressure
-					{
-						parts[i].tmp2 = RNG::Ref().between(0, 10); // Provide tmp2 for color noise
-						parts[i].ctype = PT_ROCK;
+						parts[i].ctype = PT_GOLD;
+						if (rx > 1 || rx < -1) // Trend veins vertical
+							parts[i].tmp = 1;
 					}
 				}
 
diff --git a/src/simulation/elements/ROCK.cpp b/src/simulation/elements/ROCK.cpp
index d1cfdef42..e3c47b213 100644
--- a/src/simulation/elements/ROCK.cpp
+++ b/src/simulation/elements/ROCK.cpp
@@ -16,7 +16,7 @@ void Element::Element_ROCK()
 	AirDrag = 0.00f * CFDS;
 	AirLoss = 0.94f;
 	Loss = 0.00f;
-	Collision = -0.0f;
+	Collision = 0.0f;
 	Gravity = 0.0f;
 	Diffusion = 0.00f;
 	HotAir = 0.000f * CFDS;
@@ -27,7 +27,7 @@ void Element::Element_ROCK()
 	Meltable = 5;
 	Hardness = 70;
 
-	Weight = 120;
+	Weight = 100;
 
 	HeatConduct = 200;
 	Description = "Rock. Solid material, CNCT can stack on top of it.";