Ammonite Crab | OSRS Index

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Ammonite Crab



Released		7 September 2017 (Update)
Members		Yes
Combat level		25
Size		2x2
Examine		Praise Helix!
League region		Misthalin✓

Combat info

XP bonus		+0%
Flat armour		0
Max hit		1
Aggressive		Yes
Poisonous		No
Attack style		Crush
Attack speed		4 ticks (2.4 seconds)
Respawn time		50 ticks (30 seconds)

Slayer info

Slayer level		None
Slayer XP		100 xp
Category		Crabs
Assigned by

Combat stats


100	1	1	1	1	1

Aggressive stats


+0	+0	+0	+0	+0	+0

Melee defence


+0		+0		+0

Magic defence


+0			25% weakness

Ranged defence


+0		+0		+0

Immunities

Poison		0% resistance
Venom		0% resistance
Cannons		Immune
Thralls		Not immune

Open in DPS calculator
Advanced data

Monster ID		7799
Link		MOID

Fossil Rock



Released								7 September 2017 (Update)
Members								Yes
Race								Crab
Location								Fossil Island
League region								Misthalin✓
Respawn time								50 ticks (30 seconds)
Examine								An outcrop embedded with an ammonite fossil.

Advanced data

NPC ID								7800
Link								MOID

Ammonite Crabs can be found on most of the coastal areas and northern beaches of Fossil Island, as well as in the northern Wyvern Cave.

Locations

Location	Levels	Spawns	Map	League region
Mushroom Forest	25	28	Show map	Misthalin✓
Fossil Island Volcano	25	4	Show map	Misthalin✓
Wyvern Cave - northern cave	25	7	Show map	Misthalin✓

Training Combat

Ammonite crabs are one of the creatures that are recommended for training of all levels. They are similar to rock and sand crabs as they have virtually no combat stats but have the highest health of all the crabs. Low level players should bring some food.

Like all other crabs, ammonite crabs start off aggressive but will become tolerant of the player after ten minutes. As they must be active in order to be fought, players must reset their aggression timer once they become tolerant.

A ring of wealth can be worn to automatically collect the frequently dropped numulite from ammonite crabs, for a small amount of profit.

Drops

Drop rates are estimated based on 1,170,000 samples from the Drop Rate Project, unless otherwise cited.

The average Ammonite Crab kill is worth 158.54.

Weapons

	Item	Quantity	Rarity	Price	High Alch
	Iron pickaxe	1	5/128	104	84

Fossilised currency

Item	Quantity	Rarity	Price	High Alch
Numulite	4	29/128	152	120
Numulite	2	8/128	76	60
Numulite	8	6/128	304	240

Materials

Item	Quantity	Rarity	Price	High Alch
Volcanic ash	1	6/128	98	120
Iron ore	1	2/128	73	10
Tin ore	3	4/128	30	3
Opal bolt tips	5	2/128	110	20
Coal	2	2/128	294	54
Copper ore	3	2/128	30	3

Oysters and Seaweed

Item	Quantity	Rarity	Price	High Alch
Oyster	2	12/128	106	240
Oyster	1	9/128	53	120
Seaweed	1–2	8/128	5–10	1–2
Empty oyster	1	3/128	Not sold	3
Seaweed	5	2/128	25	5
Edible seaweed	2	2/128	24	2
Oyster pearl	1	1/128	32	67
Empty oyster	3	1/128	Not sold	9

Other

Item	Quantity	Rarity	Price	High Alch
Nothing	N/A	18/128	N/A	N/A
Fishing bait	10	2/128	50	10
Calcite	1	1/128^{[d 1]}	107	18
Pyrophosphite	1	1/128^{[d 1]}	86	18
Seaweed spore	2	1/128	394	24
Casket	1	1/128	711	30

^ ^1.0 ^1.1 Calcite and pyrophosphite are always dropped together.

Gem drop table

There is a 1/128 chance of rolling the gem drop table.

Item	Quantity	Rarity	Price	High Alch
Nothing	N/A	1/256.47; Never^{[d 1]}	N/A	N/A
Uncut sapphire	1	1/512; 1/260^{[d 2]}	231	15
Uncut emerald	1	1/1,024; 1/520^{[d 2]}	467	30
Uncut ruby	1	1/2,048; 1/1,040^{[d 2]}	1,104	60
Chaos talisman	1	1/5,461.33; 1/2,773.33^{[d 2]}^{[d 3]}	245	2
Nature talisman	1	1/5,461.33; 1/2,773.33^{[d 2]}^{[d 3]}	280	2
Uncut diamond	1	1/8,192; 1/4,160^{[d 2]}	2,441	120
Rune javelin	5	1/16,384; 1/8,320^{[d 2]}	675	1,200
Loop half of key	1	1/16,384; 1/8,320^{[d 2]}	9,679	60
Tooth half of key	1	1/16,384; 1/8,320^{[d 2]}	9,771	60
Rune spear	1	1/262,144; 1/15,600^{[d 2]}^{[d 4]}	11,622	12,480
Shield left half	1	1/524,288; 1/31,200^{[d 2]}^{[d 4]}	65,036	66,000
Dragon spear	1	1/699,050.67; 1/41,600^{[d 2]}^{[d 4]}	38,083	37,440

^ The "nothing" drop is removed while wearing a ring of wealth.
^ ^2.00 ^2.01 ^2.02 ^2.03 ^2.04 ^2.05 ^2.06 ^2.07 ^2.08 ^2.09 ^2.10 ^2.11 The drop rate is increased while wearing a ring of wealth due to the "nothing" drop being removed.
^ ^3.0 ^3.1 The talisman dropped depends on where the player is located (map); typically, a nature talisman will drop above ground level and a chaos talisman will drop underground.
^ ^4.0 ^4.1 ^4.2 Only dropped if Legends' Quest has been finished; if not, a talisman is dropped instead.

Tertiary

Item	Quantity	Rarity	Price	High Alch
Clue scroll (easy)	1	1/128^{[d 1]}^{[d 2]}	Not sold	12
Numulite	5–14	27/175	190–532	150–420
Unidentified small fossil	1	3/350	Not sold	60
Unidentified medium fossil	1	3/700	Not sold	120
Unidentified large fossil	1	3/875	Not sold	180
Unidentified rare fossil	1	3/3,500	Not sold	750

^ The easy clue scroll drop rate increases to 1/121 after unlocking the easy Combat Achievements rewards tier.
^ Clue scrolls will drop as scroll boxes after the completion of X Marks the Spot.

Sound effects

Name	Description	ID
`rock_crab_attack`	Attacking	718
`rock_crab_death`	Dying	719
`rock_crab_hit`	Being attacked	720

Changes

Date	Changes
25 June 2025 (Update)	Ammonite crabs now have a 25% elemental weakness to earth spells.
26 March 2025 (Update \| poll)	Crabs can now be assigned as a Slayer task by Mazchna, Vannaka, and Chaeldar.
12 July 2018 (Update \| poll)	Ammonite Crabs now drop a maximum of 2 seaweed spores instead of 1.

Trivia

The examine text is a reference to the Helix Fossil meme from Twitch Plays Pokémon.

Fossil Island

Museum Camp

	Fossil Storage Fossil Island bank Fossil Island General Store Notice board
NPCs	Charles David Dog Fossil Collector Jardric Peter John John Mattimeo Petrified Pete Shop keeper
Items	Fossil Island fossils Numulite
Scenery	Broken spinning wheel ^(built) Chest pieces (Fossil Island) ^(built) Fire pit ^(built) Half-built Loom ^(built) Ring of Stones ^(built) Table parts ^(built)

Mushroom Forest

	Mycelium pool Wyvern Cave
NPCs	Ancient Zygomite Irene Herbiboar Maz Squirrel Weve Ammonite Crab
Items	Pyrophosphite Calcite

Tar Swamp

	Bellshroom Sulliuscep Spine mushroom
NPCs	Hoop Snake Charles Charlington Tar Monster Deranged archaeologist
Items	Hoop snake Sulliuscep cap Uncooked mushroom pie Mushroom pie Breadcrumbs Archaeologist's diary Steel ring

Fossil Island Volcano

	Volcanic Mine Petrified Pete's Ore Shop
NPCs	Lava beast Petrified Pete
Items	Soda ash Volcanic ash Volcanic mine teleport Calcite Pyrophosphite Iron ore fragment Silver ore fragment Coal fragment Gold ore fragment Mithril ore fragment Adamantite ore fragment Runite ore fragment Large rock Ash covered tome Heat-proof vessel Ore pack Dragon pickaxe (broken)
Scenery	Ash pile Boulder (Volcanic Mine)

Underwater

	Mairin's Market Pile of Fishbowls Plant door Clam Chest Hole
NPCs	Mernia Mairin Ceto Annette Puffer Fish Harlequin Fish Paradise Fish Red Fantail Fish shoal Lobstrosity
Items	Mermaid's tear Glistening tear Pufferfish Drift net Merfolk trident Seaweed spore Bowl of fish

House on the Hill

	Mycelium Transportation System Stone chest Strange Machine Strange blocks Strange stone
NPCs	Skeka
Items	Ancient wyvern shield Small enriched bone Medium enriched bone Large enriched bone Rare enriched bone Fossil island note book Ancient diary

Other

Wilhelm

Music

Source site	Old School RuneScape Wiki
Canonical source	Ammonite Crab
Content license	CC BY-NC-SA 3.0
License status	declared
Picture	Ammonite Crab · file details