Birthstone Calculator: Find Your Month's Gemstone

Birthstones are precious and semi-precious gemstones assigned to each calendar month, each carrying centuries of historical symbolism, cultural lore, and distinct gemological properties. The tradition of associating gemstones with birth periods traces its origins to antiquity—specifically the Breastplate of Aaron described in the Book of Exodus, which was adorned with twelve gemstones representing the twelve tribes of Israel and later aligned with the twelve signs of the zodiac.

In 1912, the National Association of Jewelers (now Jewelers of America) standardized the modern birthstone list in the United States to balance historical reverence with gemstone accessibility and commercial availability. While traditional birthstones reflect ancient Greco-Roman, Hindu, and biblical customs, modern lists incorporate durable, vibrant minerals such as Tanzanite (added in 2002) and Spinel (added in 2016).

• **January**: Garnet (Traditional & Modern) | Mohs Hardness: 6.5–7.5 | Deep Red | Symbol of constancy, commitment, and vitality.
• **February**: Amethyst (Traditional & Modern) | Mohs Hardness: 7.0 | Royal Purple | Quartz variety representing sobriety, serenity, and clarity.
• **March**: Aquamarine (Modern) & Bloodstone (Traditional) | Mohs Hardness: 7.5–8.0 / 6.5–7.0 | Blue-green beryl & heliotrope jasper.
• **April**: Diamond (Traditional & Modern) | Mohs Hardness: 10.0 (Hardest natural mineral) | Pure carbon crystal of invincible strength.
• **May**: Emerald (Traditional & Modern) | Mohs Hardness: 7.5–8.0 | Chromium-rich green beryl symbolizing spring rebirth and wisdom.
• **June**: Alexandrite, Pearl & Moonstone | Mohs Hardness: 8.5 / 2.5–4.5 / 6.0 | Features color-changing chrysoberyl and organic nacre pearls.
• **July**: Ruby (Traditional & Modern) | Mohs Hardness: 9.0 | Chromium-bearing red corundum symbolizing passion, vitality, and royalty.
• **August**: Peridot, Spinel & Sardonyx | Mohs Hardness: 6.5–7.0 / 8.0 | Olivine silicate formed deep in Earth's mantle and meteorites.
• **September**: Sapphire (Traditional & Modern) | Mohs Hardness: 9.0 | Blue corundum mineral of truth, loyalty, and celestial nobility.
• **October**: Opal & Tourmaline | Mohs Hardness: 5.5–6.5 / 7.0–7.5 | Play-of-color silica gel hydrate and complex boron borosilicate.
• **November**: Topaz & Citrine | Mohs Hardness: 8.0 / 7.0 | Golden aluminium silicate and yellow quartz of warmth and abundance.
• **December**: Tanzanite, Turquoise & Zircon | Mohs Hardness: 6.5–7.0 / 5.0–6.0 / 7.5 | Vibrant blue zoisite, copper phosphate, and ancient zirconium silicate.

**Example 1: Born July 14** • Assigned Birthstone: Ruby (Deep Red Corundum) • Mohs Mineral Hardness: 9.0 / 10 (exceptionally durable, second only to diamond) • Zodiac Sign: Cancer (June 21 – July 22, Water element ruled by the Moon) • Compatible Gemstones: Diamond, Garnet, Carnelian, Pearl • Historical Tradition: Worn by ancient Burmese warriors and European monarchs as an amulet of invulnerability.

**Example 2: Born October 28** • Assigned Birthstone: Opal (Play-of-color hydrated silica) & Pink Tourmaline • Mohs Mineral Hardness: 5.5–6.5 (Opal) / 7.0–7.5 (Tourmaline) • Zodiac Sign: Scorpio (October 23 – November 21, Water element ruled by Pluto/Mars) • Compatible Gemstones: Moonstone, Labradorite, Quartz • Care Note: Opals contain 3–21% water by weight; avoid ultrasonic cleaners and extreme thermal shock.