Cast aluminum? We should be so lucky. I believe it is the dreaded "pot metal"
http://en.wikipedia.org/wiki/Pot_metal or mostly zinc.
Cheap and easy to cast, it is so soft and brittle and fragile, that the Stars break. A 3 year old toddler grabbing it can destroy it in a heartbeat. That perhaps would not be so bad if the Star were made available as a separate piece apart from the [indestructible] barrel but it isn't. Also, if the cost to replace it bore some resemblance to reality. It's no wonder Tom Hanson used to tell me that these things were in stock at Caliber Motors! They break all too often.
If I needed a Star (thank goodness I do not) I would be less annoyed at paying the $800+ for it if it were cast out of stainless or brass or something other than pot metal. While the design of the star points around a circle won't win any awards for strength, the material it is cast from is substandard; maybe it was fine when the assemblies cost $50 back in 1970 but at $800 I think any MB owner should expect a better quality product.
Perhaps we should add this to the request for parts--that future iterations of this Star be made a quality product out of a quality material.
I would be remiss if I didn't add that it would be wrong to infer ALL parts are overpriced or or poor quality, or both. The new, official MB one-piece wheel covers, for example, are absolutely a stunning work of art. Highly polished stainless steel, very high quality that would be tough to equal. They stand by themselves as high quality, but are also an improvement (IMHO) over the original plated steel ones which rusted once the plating wore. I had a set of "repros" once, and they looked OK--until you put them next to the MB ones. Then the thinner, duller stainless looked horrific. The MB lawyers have since ensured that these repros (because of the 3-point star) have gone away.