Gemstone stretch jewelry is made, as the name implies, of gemstones pearls threaded on an elastic cord. This also often includes metal spacers with various styles. Stones come in many colors, size and shapes.
Some people believe gemstones emit positive energy that can enhance their wearer's health and other attributes. This alternative medicine system is called lithotherapy, and is not scientifically proven.
Beyond the mysticism and spiritual meanings, gemstones are associated with an extensive lore that relies heavily on symbolism, especially regarding their color, origin and rarity.
In fact, many so-called gemstones are synthetic or dyed, and most of what you'll find online on popular websites have unclear origins. However, this doesn't make them less visually appealling.
I've been gifted a gemstone stretch bracelet a couple of years ago and I enjoyed its stark simplicity. I've kept wearing it then forgetting it around the house ever since. I recently stumbled upon it again, and realized such jewelry could make a fun low-tech DIY project, with a lot of parameters to experiment with.
I started with black agate and aventurine pearls, which looked fine for a minimalist Merveilles-themed bracelet. I'm quite happy with the result. It was easy to make, quick, cheap, and a nice change from my usual computer-related activities.
A few days later, I made a necklace in a similar fashion, but including skull-shaped spacers. I absolutely love it.
On average, with 8 mm pearls, an adult-sized bracelet will require 23 pearls, and a necklace will need 56 pearls.