"Silver and White Gems"

Perhaps Thranduil was indeed partial to treasure, but who in his position would not be? To read royal European history is to see a labyrinth of monarchies dominated by banks, debt, and usurers. One of a king’s cardinal worries is always the state of his finances, and the rule of an entire realm requires high maintenance. To his credit, Thranduil seemed to be solvent in the late years of the Third Age, with even a surplus.  Crushing taxes? I don’t think so.  It could be considered simple prudence that he constantly looked for new sources of income. It is conceivable that emergencies were prone to befall the Mirkwood Elves, namely invasions or famine or some such thing, and recovery is always costly. Buffers of one kind or another could mean life or death for his people, renown or ruin, and he did not bear that responsibility lightly.

As financially possessive as he is rumored to be, Thranduil is NOT the greedy grasping miser some portray. He may have been frugal, certainly, but not cheap. Even so, his people knew how to be showy when the occasion permitted, and Bilbo noted that "green and white gems glinted on their collars and belts." Again, prudence on the behalf of their King shines through; not inordinate greed.

"Long will I tarry, ere I begin this war for gold. . . . Let us hope still for something that will bring reconciliation." (Elvenking Thranduil, The Hobbit)