Palo santo is the heartwood of Bursera graveolens, a tree that grows in the dry forests of Peru and Ecuador. It is burned for its smell, which is resinous and sweet and nothing like the sharpness of sage.
It is not the endangered one
The species people are thinking of is Guaiacum — lignum vitae — which is also called holy wood and is under real pressure. Bursera graveolens is a different genus in a different family, and it is not endangered. We have written this out properly in palo santo is not endangered, you are thinking of a different tree.
That is not a reason to be careless. The wood's quality depends on the tree having died naturally and lain on the forest floor for years while the resin concentrates — which means legitimate palo santo is a by-product of patience, and cutting living trees produces wood that is both illegal in Peru and smells noticeably worse. If a stick lights easily and smells thin, that is usually why.
How to burn a stick
Hold it at roughly forty-five degrees, light the end, and let it burn for half a minute or so. Then blow the flame out. What you want is a glowing ember producing smoke, not a stick on fire — a flaming stick burns through the resin fast and wastes it.
It will go out on its own, usually within a minute. That is normal and not a defect; palo santo is not designed to burn continuously like an incense stick. Relight it as often as you want. One stick will last many sessions.
Stand it in a heatproof dish, ember end up, and it will finish smouldering safely. Sand or a little ash in the dish helps.
Grades, and what the words mean
There is no formal grading system, so "first grade" or "premium" mean whatever the seller wants them to. In practice the useful signals are visual: darker wood with visible resin lines is older and better; pale, dry, uniformly light wood is younger and will smell weaker. Weight is a good proxy — resinous wood is noticeably heavier than it looks.
Sticks, chips and incense
Sticks are the raw wood. Chips are offcuts, useful on a charcoal disc or in a burner where you want a longer smoulder without tending it. Palo santo incense sticks are a different product entirely: a bamboo core rolled in a paste that includes palo santo, which burns steadily for twenty minutes or so and smells related but not identical. Neither is better; they do different jobs.
Smudge sticks → · Resin incense → · What you are actually burning →