«The extensive jeweling of the lady's costume, though frequently seen in portraiture of wealthy English women from the second half of the sixteenth, was relatively uncommon among Dutch sitters of the seventeenth century. Costume historians have noted that wealth was typically exhibited in Dutch portraiture by means of clothing that was predominantly black in colour, rather than by means of extensive jewels. Achieving a stable deep black color in fabric entailed a multi-step dying process that was not only labor intensive but that also required costly ingredients. The result was an end-product with a market price beyond the means of any but the wealthiest, so that the wearing of black was itself a marker of high economic status. And though this lady's gown appears (through the heavily discolored varnish) to be mostly brown or gold in color, rather than black, both the color and the many applied jewels may actually have been deliberately fabricated by the original artist as a more visually-interesting alternative to black. Rosemarijn Hoekstra has noted that it became customary among the Dutch after about 1640 to be depicted in imaginary dress. The unknown lady seen here well may have instructed the artist to invent for her a costume that was both suitably costly in appearance and simultaneously more stimulating to the eye than a large expanse of deep black.» (J. Stephan Edwards, A Queen of a New Invention, p. 110)
This is clearly a portrait of the same woman as the one in the portrait in the Rijksmuseum.
Equally clearly, this is a copy or another version of that painting. Not only is the lady's posture identical, so is the rings on her fingers and the chair in the background of the painting.
What would have been interesting to know is if this painting was produced at the same time in 1619, or were created at a later date after about 1640 when it became fashionable among the Dutch to be depicted in imaginary dress.
I do actually think that the lady looks older in the Huntington Portrait, but this could be a result of many things, including discoloured varnish and the technique of the painter.