Learn Portuguese (Portugal): Essa cor é linda.

essa means "that" and is used when the color you are talking about is physically near the person listening to you (for example, if they are wearing it). If the color was on you, you would use esta (this), and if it was far away from both of you, you would use aquela (that over there).

How do we know the word cor is feminine? It doesn't end in "a".

While most words ending in "a" are feminine, words ending in consonants like "r" can be either gender, so cor is just one you have to memorize. However, looking at this sentence gives you a huge clue: both the word pointing to it (essa) and the adjective describing it (linda) are in their feminine forms, proving that cor is feminine.

Would essa change if we were talking about a masculine word instead of cor?

Yes! Demonstrative words have to match the gender and number of the noun they point to. Because cor is feminine, we use essa. If you were pointing out a beautiful painting, which is the masculine word quadro, you would use the masculine form esse and say Esse quadro é lindo.

Why is the verb é used here instead of está?