The box was mentioned as with seven sides.

It was not much of a surprise to us when, underneath the feet of the mummy, we found the seven-sided casket, which you have also seen in Mr.Trelawny's room.
On the underneath part of the wrapping--linen of the left foot was painted, in the same vermilion colour as that used in the Stele, the hieroglyphic symbol for much water, and underneath the right foot the symbol of the earth.

We made out the symbolism to be that her body, immortal and transferable at will, ruled both the land and water, air and fire--the latter being exemplified by the light of the Jewel Stone, and further by the flint and iron which lay outside the mummy wrappings.
"As we lifted the casket from the sarcophagus, we noticed on its sides the strange protuberances which you have already seen; but we were unable at the time to account for them.

There were a few amulets in the sarcophagus, but none of any special worth or significance.

We took it that if there were such, they were within the wrappings; or more probably in the strange casket underneath the mummy's feet.