Christmas Gift - Candle in a Jar

A few months ago, I stumbled across oversized unscented tealights on Target clearance (I've seen similar ~2" candles at IKEA labeled 'Glimma') and couldn't resist them at just over $1 for a 6-pack. I hadn't decided quite what to do with them until I spotted 4 packs of half pint wide-mouth canning jars at Meijer for under $4. Combined with some extra aquarium gravel from a bean-bag game project; they became a fun and thoughtful, yet inexpensive, gift.

I made up 2 jars and gave the 4-candle balance of the tealights to my sister-in-law for a last-minute birthday gift. I also could see these as lovely hostess or teacher appreciation gifts.
Some modifications would be putting seasonally colored gravel in the jar, or even glass beads, sand, or seashells (just be sure your choice is not flammable/meltable). Another idea would be to mix a few drops of scented oil in with the gravel, but I'm not sure on the flammability of oils in close proximity to the flame (noting that oil warmers do not have direct contact with the candle). One could also use scented candles (I've also seen these at IKEA labeled 'Tindra').