What can we do to make UX Stack Exchange badges accessible?

In Stack Exchange, the three main Badge types (Bronze, Silver, and Gold) are differentiated with color alone. This would be challenging for users with color blind related issues to identify Badge types.

According to WCAG 2.0 SC# 1.4.1

If the information is conveyed through color differences in an image (or other non-text format), the color may not be seen by users with color deficiencies. In this case, providing the information conveyed with color through another visual means ensures users who cannot see color can still perceive the information.

https://www.w3.org/TR/UNDERSTANDING-WCAG20/visual-audio-contrast-without-color.html

So my question is, What can we do to make it more accessible?

Use different Icons for the three Badge Types maybe? Instead of using same star icons for all three?