The Siva Purana associates 8 faces with Vasu-form/Bhairava.
Source: The Siva Purana, Part I — Vidyesvara-samhita, Chapter 25 · Vidyesvara-samhita, Chapter 25 · Verse 73
8 Mukhi Rudraksha has 8 principal natural faces. The Siva Purana associates it with Vasu-form/Bhairava. Other consulted witnesses differ, and their readings are kept separate rather than blended.

Rudraksha bead (Elaeocarpus angustifolius endocarp) · botanical fruit endocarp
Trace 8 principal natural clefts continuously between both poles. Inspect both poles and the full circumference. A photograph cannot prove internal locules, species, origin or an unaltered bead. Reject carved grooves, filler, glued construction and undisclosed repairs.
The consulted Siva Purana mantra list gives “Om Hum Namah”. The item verses do not establish one compulsory weekday or universal wearing rite; follow one’s own sampradaya or a qualified guide.
Inspect with clean hands. If the setting permits, wipe briefly with clean water and dry fully in shade. The consulted authoritative sources do not establish one purification method as compulsory for every tradition.
Keep dry; use a soft dry brush; avoid detergent, perfume, varnish, prolonged soaking and heavy oiling. Rahu, litigation, business and medical guarantees remain unsupported. This is devotional information, not medical advice.
The Siva Purana associates 8 faces with Vasu-form/Bhairava.
Source: The Siva Purana, Part I — Vidyesvara-samhita, Chapter 25 · Vidyesvara-samhita, Chapter 25 · Verse 73
The Siva Purana mantra list gives Om Hum Namah for 8 faces.
Source: The Siva Purana, Part I — Vidyesvara-samhita, Chapter 25 · Vidyesvara-samhita, Chapter 25 · Mantra list after verse 81
Morphology and X-ray can document some structures but do not by themselves prove species, origin or sacred efficacy.
Source: Morphometric Characteristics of Endocarp, Seed and Embryo of Elaeocarpus ganitrus · Results and Figures 1–4 · pp. 172–177
Morphology and X-ray can document some structures but do not by themselves prove species, origin or sacred efficacy.
Source: Elaeocarpus angustifolius Blume — Plants of the World Online · Taxon record · Elaeocarpus angustifolius Blume