Luxome only uses top-grade Lyocell bamboo in its weighted blankets. Most other bamboo weighted blankets use Viscose bamboo.
First, it's important to understand how these fibers are made. Essentially, the plants are dissolved and the cellulose fibers are then regenerated and reformed into a fabric for sewing. Cellulose, being a plant-based material, is great at absorbing water and heat, which is what gives bamboo its moisture-wicking and cooling properties since it draws those away from your body.
The key difference between Viscose (a.k.a. Rayon) and Lyocell is primarily the solvent and process used to dissolve the plant-based material. Viscose bamboo uses a corrosive chemical (Sodium Hydroxide) as the solvent in order to dissolve the plant pulp. Besides using a harsh chemical on something you are going to sleep with every night, the water can't be re-used and the waste is toxic. Lyocell bamboo uses an organic solvent to dissolve the plant pulp, allowing the water and solvent to be recovered and re-used in a "closed-loop", environmentally friendly process. This creates a truly organic fabric that you can feel good about draping over you for 6-8 hours a day.