Question: how to wyvern gem mhw?
Answer: You can get Wyvern Gems from Barroth, Jyuratodus and Diablos in the Wildspire Waste, Tobi-Kadachi in the Ancient Forest and Radobaan in the Rotten Vale. Since there's a greater density of monsters that drop the item in the Wildspire Waste, that's the best place to go.