Even when you study something as simple as colours, you need a proper lesson. In the first place, we have some colours that follow the general pattern: if they end with -o are masculine, if they end with -a are feminine, and they also have a plural form. For instance:
La mesa es blanca. Las mesas son blancas. El piso es blanco. Los pisos son blancos.
Here is the group:
Blanco, blanca, blancos, blancas
Amarillo, amarilla, amarillos, amarillas
Rojo, roja, rojos, rojas
Negro, negra, negros, negras
Dorado, dorada, dorados, doradas
Plateado, plateada, plateados, plateadas
Morado, morada, morados, moradas
In the second place, we have colours which do not end with -o/-a, so they have the same ending for masculine and feminine. For instance:
La mesa es verde. Las mesas son verdes. El piso es verde. Los pisos son verdes.
Here is the group:
Verde, verdes
Celeste, celestes
Azul, azules
Gris, grises
Marrón, marrones
Remember that ‘sky blue’ is ‘celeste’, which is not the same as ‘azul claro’, meaning ‘light blue’.
In the last group, we have colours which do not change at all and always end with -a:
La mesa es naranja. Las mesas son naranja. El piso es naranja. Los pisos son naranja.
This happens because ‘naranja’ is also a fruit, ‘rosa, violeta, lila’ are also flowers and ‘turquesa’ is a precious stone. To avoid confusions, when we use these words to talk about colours, we don’t change the endings. Here is the group:
Turquesa
Naranja
Rosa
Violeta
Lila
Apart from this, we have the words ‘oscuro’ and ‘claro’ (dark and light). So we say ‘amarillo oscuro’ or ‘verde claro’ (dark yellow or light green).
Finally, we have the shades: ‘amarillento, rojizo, verdoso, azulado, grisáceo’ are the masculine forms for ‘yellowish, reddish, greenish, bluish, greyish’.
