Beyond astrological signs, there are several other symbols based on someone's birthday. Each month has a gemstone – and some even have more than one.

With about 100 gemstones out there, that's a lot of options for the 12 months, each with its own unique colors, symbolism and history.

If you know a Gemini or Cancer born in June, you might want to know their birthstone. Here's a guide to the summer month's birthstones.

June birthstone

Those born in June have a variety of gems to choose from. The month has three birthstones: alexandrite, pearl and moonstone. 

Alexandrite is a rare variety of mineral that changes color depending on the light, according to the Geological Institute of America. Some even call it "emerald by day, ruby by night." The stone appears green or blue in daylight or fluorescent light. In incandescent light, it is red or purple.

The gem takes its name from Emperor Alexander II of Russia, the Geological Institute of America reports. Its red and green colors were similar to the national military colors of imperial Russia.

Alexandrite was initially discovered in Russia's Ural Mountains in the 1830s. Today, the gemstone is primarily mined in Brazil, Sri Lanka and East Africa.

The pearl is June's second birthstone.

Natural pearls are produced by mollusks. The animals form the gem as a natural defense to keep irritants – such as a parasite or grains of sand – from entering their shell, The Natural History Museum reports.

Over the years, pearl hunting has drastically decreased natural pearl beds, according to the Geological Institute of America. As a result, most pearls on the market today are cultured pearls, which are made by technicians at pearl farms. 

Natural pearls are usually white or cream in color, while cultured pearls come in a range of hues, including pink, blue, purple, brown and black.

Pearls are associated with "purity, humility and innocence," the Geological Institute of America reports. The stone has also long been a symbol of wealth and high status.

Moonstone is June's final birthstone. 

The stone has a distinct feature known as "adularescence," which is an optical phenomenon that gives the gemstone a special glow.

This happens when light scatters between microscopic layers of feldspar in the gem, the Geological Institute of America reports. Once polished, the finest moonstones will be colorless – or white – with a sheen of blue.

Throughout centuries, many cultures associated the gem with the moon. According to Hindu mythology, it was believed moonstone was made of solidified moonbeams. In ancient Greece and Rome, the stone was associated with lunar deities. 

Moonstone is mined across the globe, including in the U.S. Other countries where moonstones is found are India, Sri Lanka, Brazil, Madagascar, Myanmar and Tanzania, the Geological Institute of America reports. 

The gem symbolizes love, passion and fertility. It is also said to bring good luck. Legend once had it that you could see your future if you put a moonstone in your mouth during a full moon.

What color is my birthstone?Learn which gemstone represents each month and what it means.

Want to learn more about other month's birthstones?

January | February | March | April | May | June | July | August | September | October | November | December

Just Curious for more? We've got you covered

USA TODAY is exploring the questions you and others ask every day. From "What's my Zodiac sign?" to "What are angel numbers?" to "How to make a vision board?" − we're striving to find answers to the most common questions you ask every day. Head to our Just Curious section to see what else we can answer.