Looking at the last two clues tells us that
Amethyst is above
Amber and that
Amber is directly above
Pearl. That means that
Pearl is in the bottom row where there's only one position.
Amber is also directly above
Pearl (not diagonally above) placing
Amber in the middle position in the middle row. We also know that
Amethyst is in the top row, but we don't yet know which position.
Looking at the second clue tells us that
Amethyst is far right of
Agate. Assuming they are on the same row puts
Amethyst in the top right corner and
Agate in the top left corner.
With
Agate,
Amber,
Amethyst and
Pearl done only
Jade and
Lapis remains.
The third clue tells us that
Lapis is far left of
Jade. That puts
Lapis in left middle row and
Jade in right middle row.
This should be the correct solution unless I've missed something.
Code:
Agate ---- Amethyst
Lapis Amber Jade
---- Pearl ----