A mala is only as strong as its weakest component; however strong the beads, the string has to bear the stress of daily handling, travel, and storage. If your string is fraying or breaking in places, it won't matter how carefully selected your beads are, for they won't last long. In contrast, a high-quality cord will give your mala the skeletal strength it requires to stay intact, drape beautifully, and stand true to form.
As well, the string holds beads in a specific way while sliding through your fingers while meditating. With flexible cords, your beads will slide effortlessly as opposed to stiff cords which will need some effort. A few minutes spent knowing the different cord types can save you hours of frustration down the road.
Cotton cord: Cotton cords are very coarse and not those shiny cords that are usually found. They also do not have much carrying capacity. They are not used much in the making of mala. However, you can try and make braids in combinations of a red and green cotton cord. Bizarre, but this helps create an illusion of color.
Nylon Cord: Another quality as per popularization is nylon. It's most preferred for mala making because of its durability, stretch resistance, and smoothness. Also, there are different thicknesses and colors to be found with it, which will allow you to match it with beads aesthetically. This is because nylon won't mind working with non-knotted and knotted malas. Easy to work with, and mostly, it's available to handle
It offers resistance to wearing for those who like to use the mala freely. Silk Cord: Silk is the most dexterous when compared to all malleable materials; hence it is luxurious and comes naturally. Juxtaposing this would be very beneficial for pussy-mauled beading. It assists in achieving knots between beads and thereby building up horrible knots at even intervals to achieve a much niche impression of professionalism to your mala. Silk is not that durable as compared to nylon and would not withstand as much heavy abuse; therefore, it should be saved only for maulas that are not subject to everyday loss.