When it comes to making a large investment in a piece, what would you say is an important part of the decision process?

A serious investment in a piece should be governed by aesthetics as well as emotion. You must have a lasting response to the item so you remain engaged with it for the longterm. Your decision making process should include a thoughtful understanding of the characteristics that give it value and the piece should merit it's price. Jewelry should be wearable, hold a memory and spark a desire. 
2 of 9