"Raw" means the hair has never been chemically processed. No perms, no relaxers, no dye, no silicone coatings. It is exactly as it left the donor's head, which means the cuticle is still intact, the natural texture is preserved, and the hair responds to color, heat, and moisture exactly like your own hair would.
Most hair sold as "human hair" has been chemically processed to make it look uniform. That uniformity comes at a cost: the cuticle is stripped, the hair becomes brittle over time, and within months it looks nothing like it did in the bag. Raw hair does not do that.
There are two types of raw hair. Raw that is mixed donor or steamed, and raw single donor that has never been steamed. The single donor, never-steamed hair is the superior buy. Every time.
When steam is applied to reshape the curl pattern, it breaks the hair's natural hydrogen bonds to force a new texture. The hair is not chemically damaged, but it has been changed at a structural level. Over time, with heat styling, washing, and daily wear, that steamed pattern can relax or shift, because the bonds were already altered once.
Raw single donor hair that has never been touched keeps the natural curl pattern of that one donor, with hydrogen bonds fully intact. It responds more predictably to heat and washing, and it lasts longer because nothing has been done to compromise its structure. You get the hair exactly as it grew. That is the S. Riviere difference: not just raw hair, but untouched raw single donor hair.