Two different substances have been sold as camphor and the older one was the more valuable. Borneol, from Dryobalanops trees in Borneo and Sumatra, was traded to China and to the Arab world from at least the sixth century and was worth many times its weight in silver. Arab and Chinese sources both describe it as the finest kind, and it entered the ketoret-adjacent trade in aromatics that ran across the Indian Ocean.
The commoner sort, from Cinnamomum camphora, is what most later trade meant. Taiwan held the largest stands, and the camphor monopoly was a significant part of why the island mattered to the Qing and then, after 1895, to Japan. Camphor was strategic because celluloid film and smokeless propellant both needed it, and until synthesis matured in the 1930s there was no substitute at scale. The extraction was carried out largely by forced and coerced labour among the mountain peoples, and the industry is a straightforward case of a ritual substance becoming a colonial commodity.
Both kinds ended up in the same religious contexts, which is why textual references are hard to resolve. A Sanskrit or Arabic mention of camphor may mean Borneo camphor, and the distinction changes the trade route, the price and the plausibility of the account.
The tree camphor is now a widely planted street tree and an invasive weed in Australia and the American South.