Can tourists take rough, uncut gems out of Sri Lanka?

No, it is strictly illegal for visitors to take rough, uncut gemstones out of Sri Lanka without a specialised commercial export licence issued by the National Gem and Jewellery Authority. If someone tries, it can lead to confiscation, major penalties, or arrest when you are at the airport.

The state keeps this restriction in place to protect local lapidary artisans and also to make sure the value-adding step of cutting and polishing stays inside the local economy. Even if you buy a very intriguing chunk of rough quartz or corundum at a mine as a cheap reminder, airport scanners are trained to spot raw minerals, and customs will take them.