It depends how much dig areas their are and how often you go down. I wouldn't say its rare but it might take a few tries.
Enjoy:)
Shieldon (Armor Fossil) are only available to Pearl, similar to how you can get Cranidos (Skull Fossil) in Diamond but not in Pearl. In Diamond, you can get a Shieldon by trading with a friend who has one in Pearl.
The Skull and Armor Fossils will be given to you by a player in Twist Mountain, he will give you a fossil on a daily basis except for the Plume and Cover Fossils.
There is armour fossil in Pokemon pearl, it is a fossil that has a shieldon in it, or you could trade with someone from diamond for a cranidos.
Root Fossil Claw Fossil Helix Fossil Dome Fossil Old Amber Armor Fossil Skull Fossil Rare Bone
Lilleep (Common) Shelidon (Also Common) Kabuto (Not all that common) Aniroth (BIG FOSSIL but rare) Omanite (Fairly Common) Areodactle (Super Stinkin' rare, I only know there in there because my friend got one after...I don't know how long)...thats about all of them. Oh, you can also get Crainidos (I think)
diamond- skull fossil- cranidos-rampardos pearl-armor fossil- sheldon-bastiodon
In Pokemon pearl you can only obtain an armor fossil before you get the National Dex. After you get the National Dex, these are the possible fossils you can get: Armor Fossil--Shieldon Claw Fossil--Anorith Root Fossil--Lileep Dome Fossil--Kabuto Helix Fossil--Omanyte Old Amber--Aerodactyl
Revived from Armor Fossil (Pearl only)
Shieldon (Armor Fossil) are only available to Pearl, similar to how you can get Cranidos (Skull Fossil) in Diamond but not in Pearl. In Diamond, you can get a Shieldon by trading with a friend who has one in Pearl.
The same way you get a skull fossil on diamond, dig in the underground till you find one.
You have to dig underground for a armor fossil and talk to the guy in the oreburgh mining museam, the fossil identifier dude.
Ok so if you have pearl you get armor fossil always you have to use action replay to get more fossils! U can buy it at Best Buy and Wal-Mart for 20$
Cranidos (Skull Fossil) are only available to Diamond, similar to how you can get Shieldon (Armor Fossil) in Pearl but not in Diamond. In Pearl, you can get a Cranidos by trading with a friend who has one in Diamond or trading with someone in the world on GTS (Global Trade Station).
You can not get an Armor Fossil in HeartGold.
use the underground tool at dig at the walls till u find one
So far I have found old amber - aerodactyl, helix fossil - Omanyte , claw fossil - Anorith, skull fosssil - Cranidos. I'm still looking for move i'l write back if there's more.there is the fossil that gets you sheidonThe fossil that gives you shieldon is an armor fossilSheildon's fossil- the armor fossil- canonly be found in Pokemon Pearl.
At the beginning of the game before getting the national pokedex you can get: Skull Fossil - Cranidos *Exclusive to Pokemon diamond Armor Fossil - Sheildon *Exclusive to Pokemon pearl After receiving the national dex you can also find: Helix Fossil - Omanyte Dome Fossil - Kabuto Old Amber - Aerodactyl Claw Fossil - Anorith Root Fossil - Lileep