There are two main varieties of avocado found around the world. One is Shepard, and the other is Hass. Hass is the more popular variant, and the one I regularly use. The ripeness of a Hass avocado can be identified by the colour of the avocado skin and the firmness of the avocado. If the avocado is soft and purple / black it is ready to eat now. If the avocado is firm and green / black, it will be ready in 1 – 2 days, and if it is hard and bright green in colour it will be ready in 3 – 4 days. To check for ripeness, always squeeze without applying your fingertips. If you squeeze hard, this can cause bruising on the inside, and show up as brown splotches when you open the avocado. If you are going to eat the avocado right away, it’s best to select a ripe one otherwise pick an unripe one, and wait for it to ripen.