What does "unsunned snow" mean?

[Escortgamer]

SPOILER ALERT
SPOILER ALERT

So I was reading about how Hester got this preternatural ability to sense if others have had sinned just like she did. And Hawthorne gives an example of a matron who has had cold snow in her heart all her life. But then he says this:

"That unsunned snow in the matron’s bosom, and the burning shame on Hester Prynne’s — what had the two in common?"

What does this mean? What is Hawthrone implicating here? That the matron doesn't really have "unsunned snow" in her bosom? It's been bugging me the whole day.

[Kelsey]

I interpreted it as "cold snow in her heart" - meaning she's been holding grudges/been upset, and those feelings haven't gone away (unsunned snow implies it's snow that hasn't been melted)- implying her feelings haven't changed; she still has a hardened heart. Hawthorne is suggesting that the matron's hard-heartedness (possibly the sin of wrath?) and Hester's adultery are both sins in their own way. Hawthorne is showing that both woman have sinned, drawing similarities between their characters.

Hope this makes sense! :)

[Escortgamer]

Kelsey wrote: "I interpreted it as "cold snow in her heart" - meaning she's been holding grudges/been upset, and those feelings haven't gone away (unsunned snow implies it's snow that hasn't been melted)- implyin..."

Incredible explanation. Thank you!