To call Grand Traverse Bay blue doesn't do it justice - I think of the color as ultramarine.
The book jacket of Blue: A History of Color states "any history of color is above all, a social history."
The author investigates how the ever-changing role of blue in society has been reflected in manuscripts, stained glass, heraldry, clothing, painting and popular culture.
Remarkably, the color we call blue is not mentioned in ancient literature or used in Western art very much, even in the middle ages and medieval times, presumably because blue pigment was just too expensive and too hard to obtain.
Not to be confused with gemstone aquamarine, ultramarine is made from a rare, semi-precious stone called lapis lazuli.
Lapis was quarried in Afghanistan and then shipped to Europe, "ship" being the operative word here - "ultramarine" means "across the sea."
Lapis lazuli was extremely expensive, out of reach for most artists, and to prepare the paint, the rocks were ground with a mortar and the powder mixed with oil and honey and then kneaded with alkali, so paintings and frescoes rarely had blue skies or blue water.
Ultramarine, if used at all, might be used for the robes of the Virgin Mary or perhaps a significant figure in a painting.
Though still ridiculously expensive and difficult to prepare, ultramarine became more available and more popular with artists in the 14th and 15th centuries.
The story of blue was influenced by the Protestant Reformation, the availability of indigo and coal balls and other pigments, scientists, philosophers and, of course, the Impressionists who painted what they saw, and they saw blue skies and blue water.
But because in 1828, a synthetic ultramarine was invented, they used French ultramarine exclusively.
On certain days, when the sun is just the right angle and the water is at just the right depth, the bay is the color of the mineral lapis lazuli, a color we call ultramarine.