Here's something I quickly came up with. I'm going to leave you the task of figuring out how to execute it with instructions.
1st obviously you would make a hexagon and you want to apply a radial gradient to your liking.
In applying the gloss effect, the liberty I took is that it is different from a circle because it is a more rigid object. The reason gloss works so well on circles is because it mimics the light affect we often see on spheres. That wouldn't be as accurate on hexagons, so I made the gloss effect cover half of the hexagon from point to point.
To create the gloss you first want to use your pen tool and create a shape that completely covers half of the hexagon. Fill this with a white to black gradient from the middle of the hexagon to the outer edge, respectively
Here's the tricky part. You want to select your hexagon and copy it because this is what we will use for our transparency mask. Select the second shape you made and go into the transparency panel
You will want to double click the symbol to the right of your hexagon. You are now in transparency mode. Ctrl + Shift + V or paste in place the hexagon you copied. Change the fill color to white. Exit out.
For bonus points. Use the second shape you built with the pen tool as part of the transparency layer as well. You can paste that on top and play around with the gradient to enhance the realism of your gloss effect.