
If you're a true beauty junkie, then you've likely noticed a HUGE beauty trend over the past year. Independently run mineral pigment retailers are cropping up like mulberry weeds (they're rampant, trust me!) I've tried a few, and overall have been impressed with the smooth texture, vivid finish, and endless range of colors that these retailers provide.
Top: TKB Lemon Drop Pop!, Lime Crime Circus Girl, Calypso Mineral Beauty Bandana
Middle: TKB Apple Green Pop!, Lime Crime Elf, Barry M Dazzle Dust Mint Green #82 (don't worry about the darker green to the right, I've got another pic for that one!
Bottom: TKB Grape Pop!, Calypso MineralsTramp, MAC Violet Pigment
As you can see from the photo, the differences in the shades are almost imperceptible. (BTW, click the images to see the photos supersized!) Looking at the yellow and green shades, Lime Crime's and TKB's are virtually identical, both in color and texture. I tried to be as scientific as I could when applying these, but any small difference I noticed (are the Lime Crime colors slightly more sheer, maybe a tiny bit more pearlized?) could easily be attributed to the amount applied, or the difference of the skin texture in the areas I applied them.
Even the notable differences weren't that drastic. Most apparent, Calypso's Bandana yellow was more opaque than it's doppelgangers. The Barry M Dazzle Dust seemed like the same base shade as the other greens, but had a dose of fine silver sparkle. Even the MAC pigment looks fairly similar to it's counterparts, though the texture of MAC's pigments are almost moist and spongy, and the finish is more metallic. I think it's safe to say these products are different than the others, because though close in color, they'd definitely achieve different effects.
Lets ponder a few more:

Top row is shown with MAC Blackground Paint Pot as a base.
Left: Lime Crime Fairy Wings Right: TKB Hilite Violet
With these pretty violet duo-chromes, I could not tell the difference no matter how they were applied.
Left: Star Gazer Eye Dust #33 Right: TKB True Green
Two more that look identical. If I were going to say any of these pigments were the EXACT same, it would be these two.
So here's my final opinion (for now, anyway.) Other than the exceptions that I talked about, all of these pigments were virtually identical. I'm not going to say they're the same exact formulations, but I'm also not ready to say they're not. All it would take is a pinch in a pound to say a shade is custom blended, that doesn't mean it will look much different on the skin.
Is it somewhat nefarious to repackage wholesale product and mark it up (literally) 4000%? Maybe, but I can assure you, this is nothing new, nor is it limited to small businesses. One major (and I mean MAJOR) cosmetics company I worked for paid around $2.00 for lipsticks that retailed at $22. The justification is that you're not just paying for the product, you're paying for the image. That means that the retailer is including all of the costs involved in producing the item you're purchasing; things like packaging, website production and maintenance, models, makeup artists and photographers that make the company's promotional images, the cost of placing those images in magazines, on-line in banner ads- the list goes on and on. That's capitalism, kids.
There's nothing wrong with buying a particular brand because you like the way their compacts look, or because you prefer supporting small businesses. Just be aware that there are alternatives out there. For anyone shopping around, here's a price by the ounce comparison of the brands I've shown in this post:
UPDATE: In October '09, Lime Crime doubled the size of their Magic Dusts, which now come in .14oz sizes for the original $12 price. The adjusted price is $85.71 per ounce.
Barry M Dazzle Dusts*: about .07 oz for $7.43= $106.14 per ounce
Stargazer Eye Dusts: about $4.96 for .063 oz= $78.73 per ounce
MAC Pigments: $19.50 for .26 oz= $75 per ounce
UPDATE: In January, '10 MAC repackaged their pigments, reducing the size to .15oz with no price change. This brings the current cost of MAC pigments to $130 per ounce.
TKB Trading: prices vary, ,most are $4.00-4.50 per ounce (no, that's not a typo, the $1.25 SAMPLE size has more product than some brand's full sizes!)
*Calypso weight per 5g jar is approximate. According to Jen, the owner, jars aren't weighed, they're just packed until they're full. Price is also an average price provided to me by the owner.
Barry M Dazzle Dust weight was determined by me weighing my own jar (after swatching) I have contacted the company for an exact weight and will update this if I hear back.