Ahhh, so rare it is to find fellow intellectuals in this region. 'Tis even rarer to find one capable of comprehending the nature of corrupted crystals.
Come to think of it, there was another─a hermit to whom the church had given sanctuary. Curious fellow. Unsociable, rather daft at first impression, yet possessed of an amazing affinity towards the scientific pursuits...
But to the matter at hand─did you say you wish not to conduct field observations, but to harvest a corrupted crystal?
Egads, man! At least take the necessary precautions so that you do not suffer from exposure to its harmful energies! I'm beginning to wonder if you've sufficient qualifications to handle such hazardous materials...
Still, your ignorance is somehow endearing. Luckily for you, I have precisely the means by which these inherent dangers may be averted. Simply store the crystal you seek within this warded pot to protect yourself from its deleterious effects. Though I suppose you will be bombarded with its energies until you place it within the vessel...
Well, perhaps it shall motivate you to work quickly. In any case, take the pot to Hahasako, a student of mine monitoring the flow of aether at Highbridge. Explain to him your quest, and he shall instruct you in the finer points of crystal harvesting.