How to Use the Birthstone Calculator
Birthstones follow the calendar month, so the birthstone calculator only asks for your birth month. Choose it from the menu and press Find My Birthstone. The result shows the stone (or both stones for months with two), its typical color, the qualities traditionally linked to it, a short description, its history and a fun fact. The lookup runs entirely in your browser.
Worked Example
A person born on October 3, 1990 selects October. The calculator returns Opal / Tourmaline: opal is the traditional October stone and pink tourmaline was added later as a modern alternative. Someone born on October 31 gets the same two stones, because the day of the month does not change a birthstone. Pair the result with the birth flower calculator for a month-themed gift.
Birthstone Chart by Month
Here is the full modern list the calculator uses. April and June have dedicated guides with more detail on the stones.
| Month | Birthstone | Color |
|---|---|---|
| January | Garnet | Deep red |
| February | Amethyst | Purple |
| March | Aquamarine | Sea blue |
| April | Diamond | Clear / white |
| May | Emerald | Vivid green |
| June | Pearl / Alexandrite | Cream / color-changing |
| July | Ruby | Vivid red |
| August | Peridot | Olive green |
| September | Sapphire | Royal blue |
| October | Opal / Tourmaline | Multi-color |
| November | Topaz / Citrine | Golden yellow |
| December | Turquoise / Tanzanite | Blue-green / violet-blue |
What Is a Birthstone?
A birthstone is a gemstone associated with the month of a person's birth. Birthstones have been used for thousands of years — ancient cultures believed gemstones possessed mystical powers and healing properties, and that wearing your birthstone would bring good luck, health, and protection.
History of Birthstones
The concept of birthstones is believed to have originated from the Breastplate of Aaron described in the Book of Exodus — a sacred garment set with twelve gemstones representing the twelve tribes of Israel. Over centuries, these twelve stones became associated with the twelve months of the year and the twelve signs of the zodiac.
The modern standardized list of birthstones was established by the American National Retail Jewelers Association (now Jewelers of America) in 1912 and has been updated slightly since — most recently in 2002 when tanzanite was added as an alternative December birthstone.
Traditional vs. Modern Birthstones
Several months have both traditional and modern birthstone assignments. For example, June has both Pearl (traditional) and Alexandrite (modern). This guide uses the most widely accepted modern list. For gemological details on each stone, such as hardness and how it is graded, the GIA birthstone guide is a reliable reference.