For a Treasure like the Gears of Madness, it was true that it was indestructible, but that was not true to an extent. To understand this would be very difficult for most until they were able to figure out the deeper portions of mysticism.
What created the indestructible effect for this treasure was the fact that it was supernaturally dense, so dense that it would make a neutron star which was the most dense object in the universe to be equal to a yarn of wool.
When a material like this became this dense that it had long surpassed the limits of the three-dimensional universes and began to encroach on the fourth Dimension–Time, it could no longer be accurately measured by any mortal or godly means, and as its hardness began to grow relative to its age and then into the space–Time Dimension which was the fifth dimension, it would soon transform again.