Analysis of Silver Filigree

The icicles wreathing
On trees in festoon
Swing, swayed to our breathing:
They're made of the moon.

She's a pale, waxen taper;
And these seem to drip
Transparent as paper
From the flame of her tip.

Molten, smoking a little,
Into crystal they pass;
Falling, freezing, to brittle
And delicate glass.

Each a sharp-pointed flower,
Each a brief stalactite
Which hangs for an hour
In the blue cave of night.