Still working through the list, but here's my first set of recommendations in (r,g,b) format. From these I'd recommend using the ore colours for aluminum, antimony and copper. I recommend salt colours for chromium and cobalt.
Aluminum
Metal: Base: (128,128,128) Specular: (224,224,224)
Ore: Base: (165,42,42) Specular: (255,128,0)
Salt: Base: (224,224,224) Specular: (255,255,255)
Antimony
Metal: Base: (96,96,96) Specular: (224,224,224)
Ore: Base: (96,96,96) Specular: (160,160, 160)
Salt: Base: (224,224,224) Specular: (255,255,255)
Chromium
Metal: Base: (128,128,128) Specular: (224,224,224)
Ore: Base: (96,96,96) Specular: (192,192,192)
Salt: Base: (102,0,255) Specular: (204,153,255)
Cobalt
Metal: Base: (126,131,126) Specular: (224,230,224)
Ore: Base: (178,73,46) Specular: (199,139,117)
Salt: Base: (51,153,255) Specular: (153,204,255)
Copper
Metal: Base: (255,128,0) Specular: (255,204,153)
Ore: Base: (0,102,51) Specular: (0,153,76)
Salt: Base: (0,204,102) Specular: (0,255,128)
Here's the completed list, with my personal recommendations marked by asterisks. Sorry for taking so long.
It may also be possible to differentiate ores by giving them unique shapes (like the long rods of stibnite, magnetite's octahedrons, etc.) Hope this helps!
Gold
*Metal: Base: (168,102,11) Specular: (249,249,221)
Ore: Base: (111,101,74) Specular: (245,244,231)
Iron
Metal: Base: (151,150,146) Specular: (205,205,204)
*Ore: Base: (117,117,117) Specular: (235,235,235)
Salt: Base: (68,18,7) Specular: (126,24,9)
Lead:
Metal: Base: (137,137,139) Specular: (199,199,199)
*Ore: Base: (95,95,93) Specular: (248,241,235)
Salt: Base: (168,31,0) Specular: (206,59,0)
Magnesium
Metal: Base: (131,129,116) Specular: (232,234,231)
*Ore: Base: (189,163,116) Specular: (239,233,210)
Salt: Base: (123,118,122) Specular: (216,216,216)
Mercury
Metal: Base: (97,97,85) Specular: (253,248,247)
*Ore: Base: (141,59,61) Specular: (205,202,216)
Salt: Base: (146,146,142) Specular: (177,176,174)
Molybdenum
Metal: Base: (97,95,94) Specular: (238,237,237,)
*Ore: Base: (215,105,47) Specular: (231,192,178)
Salt: Base: (218,117,4) Specular: (255,236,167)
Nickel
Metal: Base: (179,176,167) Specular: (254,255,250)
Ore: Base: (94,84,49) Specular: (252,247,217)
*Salt: Base: (81,213,156) Specular: (202,243,237)
Platinum
Metal: Base: (163,164,158) Specular: (227,232,228)
*Ore: Base: (156,160,161) Specular: (232,232,232)
Salt: Base: (205,81,38) Specular: (242,147,56)
Plutonium
*Metal: Base: (161,144,144) Specular: (227,207,206)
Salt: Base: (78,80,30) Specular: (125,130,64)
Promethium
Metal: Base: (81,80,78) Specular: (254,253,249)
*Ore: Base: (94,105,111) Specular: (206,210,213)
Salt: Base: (230,232,179) Specular: (232,233,194)
Rodnium (numbers based on rhodium)
Metal: Base: (144,130,119) Specular: (248,246,244)
Ore: Same as platinum/nickel
*Salt: Base: (51,37,40) Specular: (96,80,83)
Silver
Metal: Base: (143,139,136) Specular: (238,246,247)
*Ore: Base: (78,94,94) Specular: (249,249,250)
Salt: Base: (222,222,232) Specular: (219,219,230)
Tin
Metal: Base: (73,75,58) Specular: (253,253,238)
*Ore: Base: (72,81,90) Specular: (238,241,248)
Salt: Base: (250,254,253) Specular: (250,254,253)
Titanium
Metal: Base: (177,169,158) Specular: (255,254,253)
*Ore: Base: (50,49,48) Specular: (194,103,34)
Salt: Base: (137,122,116) Specular: (246,249,245)
Tungsten
Metal: Base: (169,167,154) Specular: (215,212,203)
*Ore: Base: (80,87,97) Specular: (236,235,235)
Salt: Base: (213,210,138) Specular: (234,238,178)
Zinc
Metal: Base: (160,160,162) Specular: (247,248,243)
*Ore: Base: (92,92,94) Specular: (250,250,248)
Salt: Base: (188,184,173) Specular: (251,252,247)