There are few grocery staples as beguiling as the egg.

A survey of New York City markets found prices as varied as $1.99 for a dozen to upward of $4 for just six eggs — not to mention differences in size, color, grade and packaging. Our market research reveals that the most expensive eggs aren’t necessarily the best of the bunch.

BROWN VS. WHITE

For starters, the only difference between brown eggs and white eggs is the kind of hen that lays them, said Cindy McGarrigle, vice president of industry programs and retail for the American Egg Board.

“The birds that lay the brown eggs — predominantly a breed known as the Rhode Island Red — are a little bigger. They take up more space and eat more, which is why their eggs are usually more expensive,” said McGarrigle.

THE O’S: ORGANIC and OMEGA-3s

Brown eggs, such as Horizon Organic’s ($5.99/doz.), have no additional nutritional value. What you’re paying for is the added cost to the farmer.

Similarly, for hens to produce eggs with greater levels of Omega-3 — the so-called good fat that is also found in such foods as salmon, avocado and flax seed — farmers must enhance the chicken feed with Omega-3-rich supplements, a cost that trickles down to the consumer.

Levels of Omega-3 can vary greatly, between 100 mg and 300 mg per egg, noted McGarrigle, but all eggs naturally have some Omega-3. So when Eggland’s Best ($2.54 doz) claims it has 115 mg of Omega-3 per egg, that’s more marketing tool than distinguishing feature.

If you’re concerned about getting enough Omega-3s in your diet, look for eggs with significantly higher Omega-3 numbers, such as The Country Hen ($4.19/half-dozen), which claims 310 mg Omega-3 per egg, or Giving Nature ($3.79/doz), which touts 225 mg Omega-3 per egg.

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EGG SIZE

The size of the eggs you take home is a matter of personal preference. Although for recipes, large eggs are most commonly used.

The medium-sized egg from Jack’s Egg Farm ($1.99/doz) had a significantly more compact yolk and less egg white, while the jumbo egg from The Country Hen easily had the largest yolk and the egg white generously filled a small sautee pan.

GRADE

While most eggs are Grade A we did find several eggs labeled one grade higher — “Grade AA” — including several sizes from Jack’s Egg Farm of Brooklyn.

“Grade is determined by looking at both the interior and exterior quality of the egg at the time it’s packed,” said McGarrigle. Eggs are graded by the height of the thick part of the white (closest to the yolk) as well as the roundness of the yolk, although the differences between grades A and AA are minimal.

However, in a sunny-side up cook-off, the Grade AA egg from Jack’s Egg Farm did have the thickest egg white as well as the most perfectly formed yolk.

EGG FRESHNESS

As eggshells are porous, the interior quality of the egg slowly declines over time. Consequently, the best egg is the freshest egg.

Packaging has no relevance to the freshness of eggs, McGarrigle said, with the choice of material driven by cost.

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To find the freshest eggs, a good rule of thumb is to compare expiration dates; the eggs with the farthest expiration date were packaged most recently, and have the best overall flavor and character.

Comparing the eggs in our taste test without first looking at expiration dates, we found that Jack’s Egg Farm eggs and the Country Hen eggs — with distant expiration dates — were better than the Horizon Organic eggs, which had the closer expiration date.