Candles can be made of various ingredients. How can commercial candles be identified as vegan based on the list of ingredients? Are there ways to check whether unmarked (e.g. homemade) candles are vegan or not?
It is not easy to tell if a candle is vegan because usually there is not a lot of information available about the ingredients.
As was mentioned earlier in a comment candles can be made out of paraffin which is a petroleum derivate; most of the cheapest ones are going to be made of that, or of soy wax for instance. On the other hand, the "premium" stuff is normally going to contain beeswax.
The problem usually is the stearic acid, which can be made out of coconut oil but can also be produced using animal fat. Stearic acid is used to harden the wax and provide opacity.
So even if you find a complete list of ingredients for the candle is very possible that they don't specify the origin of the stearic acid making not possible to say if the candle is in fact vegan or not.
If you're interested I would advise you to try making your own candles (in this link they use soy wax instead of paraffin) so you can make sure that they are vegan and have fun in the process!