On second thought, might have to change my answer to the mask of Tutankhamun:
The mask is 54 cm (21 in) tall, 39.3 cm (15.5 in) wide and 49 cm (19 in) deep. It is fashioned from two layers of high-
karat gold, varying from 1.5–3 mm (0.059–0.118 in) in thickness, and weighing 10.23 kg (22.6 lb).
X-ray crystallography has revealed that the mask contains two
alloys of gold: a lighter 18.4 karat shade for the face and neck, and 22.5 karat gold for the rest of the mask.
It contains inlays of coloured glass and gemstones, including
lapis lazuli (the eye surrounds and eyebrows),
quartz (the eyes),
obsidian (the pupils),
carnelian,
feldspar,
turquoise,
amazonite,
faience and other stones (as inlays of the broad collar).
A protective spell is inscribed with
Egyptian hieroglyphs on the back and shoulders in ten vertical and two horizontal lines. The spell first appeared on masks in the
Middle Kingdom, 500 years before Tutankhamun, and was used in Chapter 151 of the
Book of the Dead.
en.wikipedia.org