Authentic sandalwood, particularly Old Mountain Sandalwood (Lao Shan), is characterized by a natural, mellow, and long-lasting fragrance that emanates from the wood itself, not just the surface. Buyers should look for a high oil content, which often results in the beads 'sinking' in water (submerged grade). Examine the pore structure and grain under magnification; genuine sandalwood has fine, uniform pores. Avoid products with an overly pungent, chemical scent or those that lose their fragrance after light sanding, as these are likely perfumed or dyed imitations.