Rougui tea (Mandarin: 肉桂茶 - ròu guì chá) is indeed a type of Oolong Tea (乌龙茶 -wū lóng chá) grown on the Wuyi Mountains (武夷山 - wǔ yí shān) in China's south-eastern province of Fujian, opposite Taiwan.
The name rougui literally means 'cassia bark*', not that the tea contains any cassia, but is so-named because its aroma is perceived by some to be similar.. I'm not sure I agree although it does have a powerful aroma. The tea leaves are roasted up to three times over charcoal. The tea can be briefly be infused seven times to extract the full flavour.
Not my favourite - I'm more a green tea type.
* Most of the cinnamon sold in the USA is actually cassia.
