"Cut glass" ice lantern

This ice luminary is a variation on one from Jen Hedberg's book Ice Luminary Magic, in which a flexible insert into a bucket is used to produce a patterned surface on an ice lantern.  

For this one, we use a silicone roasting mat called "Pyramid Pan" and a commercial hexagonal Arctic Ice Lantern mold.

To make this version, I trim the curved ends of two Pyramid Pan mats.

For a small luminary, one mat is enough, but for the Arctic Ice Lantern mold, it takes two of them, overlapped inside the mold.

Here, the two mats are nested inside the Arctic Ice Lantern mold, with an overlap of several rows.  

It helps to freeze them in place with an initial inch or so of water in the bottom of the mold.  This should not come up over the indentation at the bottom, since that will provide the opening when the luminary is unmolded.  Very cold water is added after the first inch freezes, and that is allowed to freeze about 2" thick.

Here, the frozen luminary has been removed from the mold (seen in the background), by setting it upside down in a bathtub until it loosens, and gently letting it unmold onto bubble wrap.  It's been turned over to expose the opening that was created by the indentation in the mold not freezing solid.  There is a layer of ice on the outside of the Pyramid Pan mats, and that needs to be removed by freeing up the overlapped edge (using some hot water) and pulling it off.

I poured some hot water along the edge of the overlap until I could begin peeling it away from the luminary.  Once it starts pulling free, the remainder falls away easily in large sheets.  

There are a few points where this can be tricky.  It's sometimes hard to be sure the walls are thick enough, and I've had to add back the cold water and continue freezing if they are too thin.

I make a smaller version of this luminary in an extra-large Clorox wipe container from which I cut off the ridge at the top.  

For this one, I trim a Pyramid Pan to fit the mold.  This avoids having to overlap two mats, and it can be made in a home freezer.

This small lantern doesn't tolerate having a flame inside, but it can be illuminated with LED lights.

Here is one of the small "cut glass" luminaries inverted over an LED light and illuminated on a snowy night, when it would have been hard to have candles burning.