David Akers (1975/88):
The 1910-D is one of the scarcest of the early mintmarked Saint-Gaudens $20 issues, although it cannot be called rare by any means. Below full MS-65, it can be found with little or no difficulty and in gem condition it is very scarce but certainly not rare. My notes indicate I have seen two examples that I called "Superb MS-67" at the time but whether or not they would grade that high by today's standards I am not sure. Suffice to say that a superb 1910-D is a major rarity.
The 1910-D is typically well struck with very slightly satiny surfaces and a trace of granularity. Lustre is typically very good, better than on the 1908-D With Motto, 1909-D or 1911-D in general. The color is most often a light to medium orange gold, but some light greenish gold and orange ones exist as well.