Phoenix Coin Club 25th Anniversary

An interesting piece, crown sized (38.3mm in diameter), very thick (5.5mm), but weighs just 13.2 grams, so it would seem to be composed of an aluminum alloy. A very satiny to grainy overall appearance with a few cavities here and there, and the sharpness of the legends is lacking, so I was initially thinking it was cast, although I can't find any seam on its plain edge. I do detect some evidence of filing or sanding on the rim at one point, but this area is not smooth or bright. Perhaps made, adjusted, and then bead or sand blasted to impart the uniform finish? Of course, that last step ought to soften details even if it had been struck. Another peculiarity is that it's quite concave, accentuating the relief of the devices. There's also a die (mold?) crack running from the top to bottom center of the obverse.