It is in Amazons, about 41 steps south-east of the spot the map marks with that name.

And 4 down from the surface once you are there.

• 1 — Amazons, as the map itself names it
• 2 — the ground above the treasure

• Level 50 at least — there is a level door on the way in.
• Key 5010: a locked door bars the way, and that is the number of the key that opens it.
• A rope. You drop in through a hole, and a rope is how you climb back out.
• Something for black knight, beholder and scorpion — they live down there.

The chest is 4 floors under the surface. Going down over it, this is what each floor uses:

1. Ground: down through a ladder.
2. 1 down: down through a ladder.
3. 2 down: down through a hole.
4. 3 down: down through a hole.

• 1 — the way in: a ladder, ground
• → — the treasure lies this way

• 2 — a ladder, 1 down
• → — the treasure lies this way

• 3 — a hole, 2 down
• → — the treasure lies this way

• 4 — a hole, 3 down
• → — the treasure lies this way

• 1 — the chest
• 2 — the chest
• 3 — Black Knight Room Exit

There are 2 chests here under 2 quest numbers, so you can take them all.