How we cite our quotes:
The hue of the orbs was the most brilliant of black, and, far over them, hung jetty lashes of great length. The brows, slightly irregular in outline, had the same tint. The "strangeness," however, which I found in the eyes, was of a nature distinct from the formation, or the color, or the brilliancy of the features, and must, after all, be referred to the expression. Ah, word of no meaning! behind whose vast latitude of mere sound we entrench our ignorance of so much of the spiritual. The expression of the eyes of Ligeia! How for long hours have I pondered upon it! How have I, through the whole of a midsummer night, struggled to fathom it! What was it – that something more profound than the well of Democritus – which lay far within the pupils of my beloved? What was it?" (4)
Her "expression" is something like what the French call the je ne sais quoi (the literal translation is "I don't know what," but it's really meant to imply an intangible quality that makes something or someone distinctive or attractive). You know it's there, but you can't find the words to describe it.
And thus how frequently, in my intense scrutiny of Ligeia's eyes, have I felt approaching the full knowledge of their expression – felt it approaching – yet not quite be mine – and so at length entirely depart! And (strange, oh strangest mystery of all!) I found, in the commonest objects of the universe, a circle of analogies to that expression. I mean to say that, subsequently to the period when Ligeia's beauty passed into my spirit, there dwelling as in a shrine, I derived, from many existences in the material world, a sentiment such as I felt always aroused within me by her large and luminous orbs. Yet not the more could I define that sentiment, or analyze, or even steadily view it. (5)
It seems a contradiction that Ligeia's unique, indefinable beauty could find expression in the "commonest objects."
Let me speak only of that one chamber, ever accursed, whither in a moment of mental alienation, I led from the altar as my bride – as the successor of the unforgotten Ligeia – the fair-haired and blue-eyed Lady Rowena Trevanion, of Tremaine. (18)
By the time the narrator gets around to describing Lady Rowena, it seems he's run out of gas. He can only spare a few words on her.