Most of my knowledge of the value of silver and gold comes from Adam Smith's famous work, On the Wealth of Nations. The indication I got from it was that by weight or volume, silver was never worth more than gold; not even close. But the way this question is worded, all one would need is a counterexample.

A quick search tells me that by volume, there is roughly 20 times more silver than gold in the earth's crust. For most of history, Rarity alone influenced the price of these precious metals. They only served luxury purposes; they didn't have any properties that were critical for anything other than luxury goods like art or jewelry.

Bronze was never more valuable than silver, however, tin, the element added to copper to make bronze may have come close in some regions. Unlike silver and gold, bronze did serve a practical purpose. Bronze can be work hardened such that it can maintain a sharpened edge. This property, combined with the rarity of tin in many areas meant that tin was a critical object of trade. In the bronze age, a civilization that had access to bronze could make weapons to conquer a civilization that did not. So if you were in a region that did not have tin, you set up trade routes, and traded whatever you could to make sure you got it.

As far as a specific instance where tin was trading at or above its weight in silver, I'm afraid I don't know about that one way or another. For all I know, it has never even come close. But I figured the above information was better than nothing.