This is a purple "zi cha" varietal of tea from Jinggu that was processed into an air-dried black tea. Normally this varietal is processed into Moonlight White Tea (月光白), which is a classic Yunnan white tea.
Instead of processing into white tea, the wilting was allowed to progress for much longer, allowing the tea leaves to become brown in color (like Black tea). Then the next day the tea leaves are dried using air which is continuously circulated until the tea is fully cured.
The resulting tea has character of both black tea and moonlight white tea. Sweet, fruity, and thick, with no real bitterness and minimal astringency. Due to the simple no-heat processing this tea if kept sealed in a pouch or clay jar will age wonderfully!
Below is a short video shot by the tea grower that shows the garden where this tea comes from.