I dug this up in the float along with some broken milky and smoky quartz crystal points at Wigwam Creek. I think it is milky, clear, and smoky quartz, but the dark part has me confused as it shows a rainbow sheen on it's surface like oil would. Is the dark area here smoky quartz or is it something else?

I thought these were odd also. These are two quartz crystal points I found. They are milky quartz on the outside but smoky inside. Some others I found were pure milky or pure smoky. Are these common?





Thanks!

Sweet finds Dave! It look like smokey quartz to me. Hard to tell just by a picture though. Both Woody and Astrobleme have found pieces with layered smokey and milky quartz before also. Very cool how it forms in layers like that!!

Yesterday I took the first specimen and two of the crystal points to Desert Gems in Lakewood and they told me the opaque mineral isn't milky quartz, it's amazonite that formed in an environment that was lacking copper so it's basically colorless instead of the normal blue/green color found in the area.

I am very familiar with that area and have many smokey quartz pieces that have a second growth or coating of the foggy white milky quartz.
I also have found some that have very clear quartz coating over the dark smokey quartz. This is very common for the area.

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I think Mike is correct on that white over growth being a milky quartz also.....I've seen quite a few finds from that area which were very similar to those you've found.
Not to say that you couldn't find amazonite with the quartz but who ever told you that at that shop was mistaken.
If it were what they said it was it would not even be referred to as amazonite.....it would have then been tagged with the proper name of microcline which is what amazonite is (a blue or green tinted microcline) The blue/green coloring is caused by a slight portion of lead when forming as I understand it......not copper. A milky white but still crystal shape is void of the lead and would then be microcline.

A great website you can use to check on stuff like this is Mindat.org......That website specializes in "mineral data" and it's very accurate in that regard.
Here's a link to their amazonite page which you can see how it's part of the microcline family within the feldspar grouping of minerals. I get lost in all the info offered for each mineral when I start reading there. Great resource to have on hand when attempting to id a piece.