"It's beautifully cut and polished to a mirror-like surface."
The Yellow Gemstone is an event item exclusive in the remake version of Resident Evil.
The Yellow Gemstone is placed in a deer head hanging on a wall in the Spencer Mansion. It can be recovered by climbing a crate to reach the deer head, but the player must make sure an eagle statue with a rotating head isn't looking at them or the gem will be locked into the deer head by an anti-theft mechanism.
It is used to get a MO Disk from the tiger statue on the first floor of the Spencer Mansion.