I would like to attach a rectangular piece of wood (without drilling through the wood) to a string to make a necklace. The piece of wood should be attached with a knot to its extremity, and hang vertically. I would like the knot to be small, easy and aesthetic. I am thinking about using a fisherman's knot to make a loop out of the necklace, and then somehow attach the wood to the loop - but it might be more clever to attach the wood to the two ends of the string.
What type of knot should I use?