Add the colour to the Tenax Marble and Stone Glue before the catalyst and match the hue.
This is the Tenax Epoxy Glue Colour is a low cost way to colour your epoxies. And makes matching your glues simple. Tenax epoxy based colours can be used with all standard stone epoxies. Each colour comes in a 2 ounce squeeze type tube. This low cost colour goes a long way. It is made by Tenax, the oldest name in the business.