Linked from
The 11 pages that link to Ultramarine, each with the reason it gives.
PigmentBroader topic: Its costly natural source shaped the use and symbolism of blue in painting.
AzuriteCompared with: It is a distinct historic blue pigment, unlike ground azurite.
Lapis lazuliBroader topic: Grinding and processing the rock produced this prized pigment.
LazuriteBroader topic: Ground lazurite-bearing lapis was the source of natural ultramarine pigment.
Yves KleinRelated: Its intense hue supplied the basis for Klein’s signature blue.