MAC Ruby is a slightly cool-toned, light-medium red with a satin finish. It is a limited edition lipstick that retails for $21.00 and contains 0.1 oz.
Ruby is described as a "mid-tone blue red [with an Amplified finish]." It's a bright, medium red with very subtle blue undertones--it almost looks warm-toned against my complexion. It had good, nearly full color coverage, and it applied smoothly without settling into lip lines. It wore well for almost six hours and left a stain behind, and I didn't have any feathering issues with this shade. I would describe it more as a neutral red. There are a surprising number of shades that are similar, so this list isn't quite exhaustive. MAC True Love’s Kiss (LE, $16.00) is a touch darker. MAC Head in the Clouds (LE, $16.00) is lighter. Estee Lauder Vengeful Red (P, $30.00) is similar. Anna Sui Minnie Mouse (01) (LE) is similar. Marc Jacobs Beauty Neo-Noir (126) (P, $30.00) is a touch darker. Edward Bess Eternal Passion (P, $32.00) is similar. Maybelline On Fire Red (P, $7.49) is slightly warmer. MAC Everyday Diva (P, $22.00) is very similar. See comparison swatches / view dupes.
FURTHER READING: Formula Overview, which is a detailed review of the range as a whole.
Formulated to shade, define and showcase the lips, M·A·C Lipstick is available in every nuance of your favorite color and high-fashion texture. It's the iconic product that made M·A·C famous. AMPLIFIED CREME (A): Ultra-creamy. Quietly shiny. Color-packed! Hi-res: hi-impact. CREMESHEEN (C): Creme-based lipstick that imparts bright full color, with a soft and supple shine. FROST (F): Excellent color payoff with medium to high frosted shimmer-and-shine finish. LUSTRE (L): Demi-sheer with wet-look lustre finish. Very slick. Makes lips look soft, smooth, ultra-moist. MATTE (M): Pigment rich with intense color pay-off. No-shine, all matte finish. SATIN (S): Color-rich. Soft satin, semi-matte finish. Conditions while adding intense color.