You are right to feel a bit adrift in dividing the estate, since one sibling's treasure may be another sibling's trash.
The value of the estate is what must be divided, but there are different ways to value and divide each asset.
Clearly, the “value” of a sentimental object is determined subjectively -- not by an appraiser, but by the beneficiary who wants to receive it. Since it seems that the items that are giving you the most trouble are those with sentimental value, you may get the best steering by asking your sisters how they feel about individual items. Mary might have secretly been pining for the inexpensive cocktail ring, while the gold wedding band suits Jane's tastes perfectly. And in such evaluations of "fairness," money is no object.
Some siblings successfully make dividing up their parents' property a sort of festive affair. They might gather together with a list of the property that's to be divided and take turns picking off the list.
An auction for personal property is also often a great solution, especially if you and your siblings can't readily agree upon value or upon who will receive a particular item.