"Mineral Blue is a soft gray-blue as is sometimes seen in rocks and minerals. While it is not so bright as most other blues available to the artist, its subtlety is very useful in many situations. Like its darker cousins, Paynes Grey and Midnight Blue it is best off being thought of as a cool blue grey, or as a soft and muted blue for mixing purposes. It is similar in usage and colour to the colour known during the Renaissance as Ultramarine Ashes. In those days Ultramarine Blue was made by crushing lapis lazuli gemstones and then chemically extracting the blue colouring agent by using lye. This was only partially successful and some blue would remain in the lapis lazuli, so it would be repeated twice more. The blue obtained in the first two times were sold as Ultramarine Blue, first quality, and a cheaper second quality version as it wasn???t as intensely blue as the first. By the time the third extraction process was done there was very little blue colouring material left, and it was mixed with the grey gem matrix material. This was not sold as a bright blue and was called Ultramarine Ashes. Compared to the first two grades this was sold very cheaply. The old masters found this ash colour to be useful for stormy skies, and misty landscapes, and for mixing with earth colours to get the range of soft greys found in rocks , or in the shadows of white fabrics.
These sort of greys and neutrals are very common in nature and yet there are few pigments that have these sorts of colour. This is why mixtures such as Paynes Grey arose in the 18th century to help depict moody sorts of landscapes, especially cloudy and rainy scenes. Mineral Blue continues that tradition. It is more blue and lighter than Paynes Grey and is reminiscent of the sorts of grey blues found in the Southern Ocean. It is generally a useful colour when painting water and in moody landscapes. Mixed with Yellow Oxide it produces the sorts of greenish greys found in the leaves of many eucalyptus trees and so is of great value wherever they are found. Mineral Blue is a moody blue perfect for atmospheric scenes.