It's a solidly earthy, slightly mossy, and almost "damp" smelling patchouli. There's a nearly undetectable sort of smoky sweetness to it, and it has just the slightest hint of spice. I use it regularly and fairly sparingly, and I'll note that in my experience, it doesn't project very much, even when I apply more- it sticks pretty close to the skin and fades after a few hours, so if you're looking for a patchouli perfume oil that's more of a soft skin-scent than a powerhouse, this is a nice one. I think I only paid about $7 USD, so it's very affordable and will last you a long time. It also layers nicely with other perfumes if you're looking to add or amp up the patchouli in them.
I believe that Spiritual Sky has been around since the late sixties and producing oils since the seventies, and although it's quite likely that the formula has changed since then, it does seem very old-school to me (packaging included)- though admittedly I cannot confirm the validity of this statement as I wasn't around.
Vibe-wise, however, this IS your grandma's patchouli- there is nothing too refined, overly complicated, or modern about it. I am a patchouli enthusiast, and as much as I love my more elaborate patchouli-blend perfumes, there's something about just straight patchouli oil that hits like nothing else sometimes.
