Rarer still?

[pdh0224]

Dear teacher,

The Met's "Madonna," however, is one of the few that Duccio created as individual works of art and was never part of a larger assemblage. "It's the artist's complete thought on the subject,'' said Keith Christiansen, a curator of European painting at the Met. Rarer still, it remains in its original frame, singed along the bottom edge by devotional candles.

Q : What does "Rarer still" mean?

Q2 : What does "singed along the bottom edge by devotional candles" stand for?


p.s : Met is a name of a museum. "Madonna" is a name of a paiting.

[Alan]

1. It stands for 'What is rarer still', a kind of clausal conjunct meaning that that which follows (i.e. the fact that it remains in its original frame) is even more unusual than that which precedes (i.e. the fact of its representing the artist's complete thoughts on the subject).

2. It refers to 'it' (the painting).