You must break ice pillars and spawn an ice statue to obtain the heart.
To even get a chance at the heart, the pillar must not be broken with overkill damage. That is, if it has 10 health left and you do 11 damage, you won't even get a chance at getting the heart.
Only once you break the pillar with no overkill damage, you will have a high chance of getting the heart.
The pan you get from 2 Mark of Ignea rewards.
Using the pan is the most ideal method of obtaining the heart since you can't overkill with 1 damage.
Taking all your armor and accessories off and doing damage with your bare fists do 10 damage.
Try to get the ice pillar as low as possible before trying to hit it with a pan or bare fists; reference below.
Once you can't see any red left in the bar, that is when you use your fists or pan.
The below 2 pictures are for reference for comparison.
1st has a tiny bar left and you can clearly see red in the 2nd.
Only 11 statues appear per day. This resets at 12:00am KST.
Ice pillars will keep re-spawning until all ice statues are created for the day.
The 1st picture are spawn locations for pillars.
An ice pick can also randomly drop if you break an ice pillar.
It also deals the same amount of damage as the pan, dealing 1 damage.
(Bottom right seed can only be obtained by entering and exiting the map multiple times)
Island Heart
The island heart can be obtained by completing the purple quest on the island.
You enter the map at a random spawn location.
Orient yourself by traveling towards any corner. Once you reach a corner, you can figure out where you are and then work your way around the map from there.
Island Quest
The purple quest is received at the blue dot in the picture above.
The purple quest requires you to go back to any one of the red dots in the corners.
You must have the item whale oil in order to complete the purple quest to receive the Heart.
Whale oil can be obtained by completing the Notos Island daily 6 times.