When agarwood formed in Aquilaria trees, they are created very differently.
Depending on their patterns, these wood logs would be used for a different purpose.
Only several types provide "annual ring" pattern, perfect for beads. These are rare which contribute to the cost of making beads. Below are expensive logs which could be occurred in the natural or wild environment only:
As beads (bracelets and necklaces) are generally precious, especially if made from the above logs, unscrupulous sellers invested some tricks in darkening beads, creating a luxurious antique look.
Some highly resinous pieces are not quite suitable for filing to make beads as below.
To give you a general idea, only 300 g finished beads products made from 1kg of wood log. The above piece was sold at $100,000 per kg, which would be non-sense to waste as such ratio. Hence any beads you see that are 100% dark usually non-genuine agarwood or with oil injection or a cheap trick.
Please note, at room temperature, it is possible to detect some subtle scent from the above logs but do not expect a strong fragrance from them or beads unless they are heated.
The below wood logs are Buaya gaharu (crocodile agarwood)
When heated, these woods provide a strong muddy smell, simple woody note. When used in oil distillation, its texture was cloudy white, pungent. Unlike agarwood, it does not develop or dry down to a different note.