You can Acquire it from the Large Boy on Route 36.
It's the same with heartgold and soulsilver. Theres a fat boy near the enterance of the ruins of alph talk to him and he should give you HM Rock smash
cut, surf, fly, rock smash, rock climb, strength, and waterfall In Diamond, Pearl and Platinum there is HM defog. In HeartGold and SoulSilver there is HM whirlpool.
there's no moss rock in heartgold/soulsilver. To get it you need to trade from a different game. Sorry!
Nope
Victory road in pokemon heartgold and soulsilver is the final testing area for the trainer before they get to the elite four and the champion. I is difficult to navigate and will contain many high level pokemon. You will also be required to have the HM rock smash, rock climb, strength, surf, and waterfall.
You smash a rock in the Ruins of Alph by using Rock Smash and under 1 of them there will be an old amber.
In SoulSilver and HeartGold you go to the Ruins of Alph and use rock smash until you get Old Amber.
you defeat a gym leader
Hiker on route 36
Ruins of Alph by using Rock Smash on the Rock Smash-able rocks. I believe the Dome Fossil is only found in Soulsilver, I could be wrong.
youy will need flash, all hm's, and rock smash. all the rest you might find useful in battle such as rest, toxic, and thunder.
There is no mossy rock in HeartGold. There is not one in SoulSilver, either. A mossy rock is only found in Pokemon Diamond and Pearl. You must trade for a Leafeon to get one in Pokemon HeartGold.