The other day I was standing in line at a swank beauty spa to pay for a service when a total stranger walked up to me and commented, “What a nice tan you have!”

I didn’t know what to say. I’m not tanned. This is my color. I am a brown, dark featured Mexican American woman.

I looked around me in line and realized that I was the only brown-skinned person in the establishment. Still, why did she assume I was tanned? Is it because I dress nicely?

“Okay, Alicia,” I said to myself. “Don’t be so sensitive.” Maybe she wanted to make conversation, forge a connection. But why then comment on what a “nice tan” I have? Why not say, “What nice skin you have”? Besides, I find the whole idea a bit strange.

I have to wonder, though, is color, coloring the issue?

I recently dated a man who insisted to me I was Caucasian; a classification that the 2010 Census also endorses. Check the form – it asks you to distinguish your origin if of Hispanic descent but then right below leaves Hispanic off as a racial classification. One has to either check Caucasian or write in Hispanic under Other.

Though Hispanic is apparently not a race, I told my date, “No. I’m Mexican American.” He replied, “But I don’t see you as not White.” Poor English aside, I recognized the quagmire: color and race. Even in his response he confused the two.

I asked him if the people that worked on his ranch in Texas were Caucasian. I knew that he employed many Mexican Americans. “But you’re not like them,” he blurted. Then he paused, unsure of what to say. Finally, he continued, “So you mean, that when you’re in a room full of white people, you feel different?” He’s a Harvard Business School graduate.

Actually, when I enter a room I don’t immediately assess the color profile of the room. It usually doesn’t even occur to me. It’s the same sort of blur I experience when I’m in a room full of men at a business conference. It generally doesn’t matter for my purposes. But I would be lying if I said that it never occurs to me, because it does and sometimes it’s conveniently pointed out.

Because I have dark skin, I realize that I am often conspicuous among my fairer brethren. I’ve been taught that I am by women in tony shops asking me to hold their bags. Oh yes, I have all manner of stories like that – being asked at a charity event if I was So and So’s nanny, mistaken for the maid at a hotel, questioned for sitting in first class on a plane and forced to produce my ticket stub to prove I had purchased the ticket – I could go on.

I tend to think that the reason I encounter some of these experiences is because I operate in environments that are decidedly not diverse. Let’s face it; private equity and venture capital are not the normal stomping grounds of U.S. Hispanics.

Or are they? Here’s where it gets tricky for Hispanics. We’re not all brown. I once worked with a fair-skinned, hazel-eyed woman at Goldman Sachs & Co. in New York who confessed to me at lunch one day that she was “half-Mexican.” Her father was German and her mother Mexican American. She urged me to never tell a soul.

Sometimes I think the Census should give up race classification altogether and ask people to mark the shade of color they are. But it’s so much more than color, isn’t it?

Why do U.S. Hispanics have the highest high school dropout rates and second highest representation in state prisons? Those drop outs and jailbirds are not all brown-skinned. I can only speculate that the reason I have to ask these questions is the same reason people assume I am tanned.

The lady in the spa? I believe that not only did it not occur to her that my skin is actually brown and not merely tanned, but also that I could be a Mexican American. To me, to assume brown skin is tanned skin is the same thing as calling a Mexican American a Caucasian. It subsumes a whole swath of people - a race, if you will. A race, subsumed, I fear, keeps that race invisible and therefore powerless.

Hispanics are the fastest growing segment of the U.S. population. Yet, from the attention we’re paid – from representation on television (no, we don’t all watch Univision – who by the way doesn’t do much to dispel the skin color issue) to the percentage of advertising dollars spent on the market, you’d be hard-pressed to guess that.

A subsumed race is also a denied race – its rich history, struggles, achievements and even its place are lost. Our place? Well, we can be found across conference room tables, at podiums, and even at ritzy spas. Just not as a racial classification on the U.S. Census form.

Oh, it happened again yesterday. A woman told me I had a nice tan. This time I said, “Thanks, I was born with it.”