I'm always looking for daguerreotypes of drawings or paintings, but hadn't thought to look for CDV's of the same until coming across this one while digging through a box of old photos and ephemera in Maine this week. It looks to me that the portrait photographed was done in charcoal, with particular attention paid to the subject's earrings and brooch. Certainly it was drawn by an academically trained artist, and I would guess a known and notable one. The photograph was taken by Edward L. Allen (1830–1914) of Boston (the card is printed with his wonderful logo on reverse). Allen kept a studio on Temple Place (c. 1868–1871), which would be the date range on this I believe.
2 9/16 x 4 1/8. Good condition, with scattered smudges/light stains to the card.