There is gold and abundance of costly stones,
but the lips of knowledge are a precious jewel.
Like the previous proverb, this one presents a scenario that goes against the common wisdom of the marketplace. There are those who train to become experts in identifying pure gold and costly jewels. Such items are valued for their beauty, but their market value is based on their rarity. However beautiful a jewel may be, if there are many comparable then its value diminishes.
The lips of knowledge are a precious jewel. In comparison to the amount of gold and costly stones, they are more rare and all the more to be valued. There are many persons who know lots of information; many who are clever. But the lips of knowledge that Scripture has in mind are rare and valuable beyond these others. For this knowledge is that which teaches the fear of the Lord and leads those who listen and obey along the path of eternal life. This knowledge imparts wisdom that is able to discern what is of true value and what is mere imitation. This knowledge blesses and reaps blessing. It cannot be stolen, and the more it is given, the purer and more abundant it becomes in the giver.
But again, it is also rare. For even those who have found the truth of the gospel still mix in false teaching. Even those who think they are imparting the true Word are often imparting worldly wisdom. The lips of knowledge - of gospel wisdom - are precious; and when you hear them, value them for what they are, and adorn yourself with them through obedience. Those are the costly stones most beautiful to adorn.