Why Do Flowers Have Different Colours?

I heard that rose has different colours because of the minerals in the place it's grown in, but i don't know about other flowers.
Hope that'll help you  : )

The colors of flowers help to ensure the continued progeny of flowers. The bright colors attract insects and birds so that they come feed on them and spread their pollen. The pollen that is carried to other places by these consumers of flower nectar germinates in favorable conditions and the plant may grow in a place where an insect might have tracked it to.
The flowers reward the feeders for spreading its seed by producing a sweet substance known as 'nectar' that they may consume. Honey bees consume it and make honey. While the flower whose nectar they suck benefits by spreading their seed. What happens is that as insects land on flowers to feed on them, some of the pollen from the flower sticks to their feet. Then, when they fly off and land on another place or crawl to another place, they track this pollen with them.
Some flowers even have patterns and lines that actually guide the insects on where exactly on the flower they would find nectar. Without insects, these flowers cannot germinate. That is actually a big threat to natural ecosystems. Often to finish off a pest insect, we spray insecticide all around an area, thus killing all the insects in it. When the insects all die out (or migrate for other reasons which have disrupted their habitat such as noise, exhaust fumes and excessive heat), the flowers are left in a 'barren' state because nothing can carry their progeny forward. This may cause massive dieback of flowers in an area.