Birthstone Calculator
Find your birthstone, birth flower, and zodiac sign from your birth month. Enter values for instant results with step-by-step formulas.
Formula
Birthstone = Month-to-Gemstone mapping (standardized 1912, updated 2002)
Each birth month is assigned one or more gemstones based on the standardized list established by the American National Association of Jewelers in 1912 and updated by the American Gem Trade Association. The calculator also maps birth flowers and zodiac signs for each month.
Worked Examples
Example 1: July Birthday Birthstone Lookup
Problem: Find the birthstone, birth flower, and zodiac signs for someone born in July.
Solution: July birthstone: Ruby - a red corundum known as the king of precious stones. Birth flower: Larkspur. Zodiac signs: Cancer (July 1-22) and Leo (July 23-31). Ruby symbolizes passion, protection, and prosperity. It has a Mohs hardness of 9, making it the second hardest natural gemstone after diamond.
Result: Birthstone: Ruby | Flower: Larkspur | Zodiac: Cancer/Leo | Meaning: Passion and protection
Example 2: October Birthday with Dual Birthstones
Problem: Find the birthstone options for someone born in October.
Solution: October has two birthstones: Opal and Tourmaline. Opal displays a unique play-of-color effect with shifting rainbow hues. Tourmaline comes in virtually every color, with pink and green being most popular for birthstone jewelry. Birth flower: Marigold. Zodiac signs: Libra (Oct 1-22) and Scorpio (Oct 23-31). Both stones symbolize hope, creativity, and confidence.
Result: Birthstones: Opal or Tourmaline | Flower: Marigold | Zodiac: Libra/Scorpio
Frequently Asked Questions
What is a birthstone and where did the tradition come from?
A birthstone is a gemstone associated with a particular month of the year, and wearing your birthstone is believed to bring good luck and protection. The tradition dates back to the Breastplate of Aaron described in the Book of Exodus, which contained twelve stones representing the twelve tribes of Israel. Over centuries, these stones became associated with the twelve months of the year and the twelve zodiac signs. The modern standardized list of birthstones was established in 1912 by the Jewelers of America (now the American Gem Trade Association). This list has been updated several times, most recently adding tanzanite for December in 2002.
What is the most valuable birthstone?
Diamond, the April birthstone, is generally considered the most valuable per carat of the traditional birthstones, though fine rubies and emeralds can actually exceed diamond prices at the highest quality levels. A top-quality Burmese ruby can sell for over $1 million per carat at auction, which is more than most diamonds. Alexandrite, one of June's birthstones, is among the rarest gemstones on earth and can command prices of $50,000 to $70,000 per carat for fine specimens. Emeralds with excellent color and minimal inclusions are also extremely valuable. The least expensive birthstones are generally citrine, peridot, and garnet, which are more abundant and therefore more affordable.
Can I wear a birthstone from a different month?
Absolutely, there are no rules restricting which gemstones you can wear regardless of your birth month. Many people choose gemstones based on color preference, personal meaning, or fashion rather than strictly following birthstone assignments. Some people wear birthstones of loved ones to feel a connection to them. Others choose stones based on metaphysical properties they believe in, such as wearing amethyst for calmness regardless of birth month. In the jewelry industry, birthstone jewelry is marketed based on birth month, but gemstone enthusiasts and collectors often appreciate stones from every month. The most important factor in choosing a gemstone is that it resonates with you personally.
How should I care for my birthstone jewelry?
Care requirements vary significantly by gemstone hardness and composition. Diamonds (April) and sapphires (September) are extremely hard (9-10 on the Mohs scale) and can be cleaned with soap, warm water, and a soft brush. Softer stones like opals (October, 5.5-6.5 hardness) and pearls (June, 2.5-4.5 hardness) require much gentler care and should never be exposed to ultrasonic cleaners or harsh chemicals. Emeralds (May) are often oil-treated, so avoid steam cleaning. As a general rule, remove gemstone rings before heavy manual work, exposure to chemicals, or swimming. Store each piece separately to prevent harder stones from scratching softer ones. Annual professional inspection helps maintain settings and catch loose stones.
How accurate are the results from Birthstone Calculator?
All calculations use established mathematical formulas and are performed with high-precision arithmetic. Results are accurate to the precision shown. For critical decisions in finance, medicine, or engineering, always verify results with a qualified professional.
What formula does Birthstone Calculator use?
The formula used is described in the Formula section on this page. It is based on widely accepted standards in the relevant field. If you need a specific reference or citation, the References section provides links to authoritative sources.