Birthstones

T H E   B I R T H R I G H T

The miracle of our land’s speech—so known 
And long received, none marvel when ’tis shown!

We have such wealth as Rome at her most pride
Had not or (having) scattered not so wide;
Nor with such arrant prodigality
Beneath her any pagan’s foot let lie...
Lo! Diamond that cost some half their days
To find and t’other half to bring to blaze
Rubies of every heat, wherethrough we scan
The fiercer and more fiery heart of man
Emerald that with the uplifted billow vies.
And Sapphires evening remembered skies
Pearl perfect, as immortal tears must show.
Bred, in deep waters, of a piercing woe;
And tender Turkis, so with charms y-writ.
Of woven gold, Time dares not bite on it.
Thereafter, in all manners worked and set.
Jade, coral, amber, crystal, ivories, jet—

Showing no more than various fancies, yet
Each a Life’s token or Love’s amulet...
Which things, through timeless arrogance of use.
We neither guard nor garner, but abuse;
So that our scholars—nay, our children—fling

In sport or jest treasure to arm a King;
And the gross crowd, at feast or market, hold
Traffic perforce with dust of gems and gold!

—Rudyard Kipling, from Debits and Credits, 1919–1923

Birthstones are a fascinating aspect of the gem and jewelry world, and are derived from early beliefs regarding the one’s time of birth and its relationship to the planets. Wearing a certain stone as protection against illness and misfortune, or another gem for good luck, eventually developed into the birthstone systems of today.

Modern Birthstones

From these early systems, comes the modern birthstone system.

The Western birthstone system originates from the writings of Josephus (1st century AD) and St. Jerome (5th century AD). Both trace the custom to the gems of the Hebrew High Priest’s Breastplate. Over time, the birthstone custom died, only to be revived again in 18th-century Poland.

Zodiac Gems

Long before the modern 12-month calendar was invented, astrologers assigned certain gemstones to the 12 signs of the zodiac based on the symbolism and metaphysical powers each stone was believed to possess.

Indian Planetary Gemology

In ancient India, beliefs regarding the planets and their relationships with stones also is found. This has developed into what some today refer to as “planetary gemology.” In such systems, there are nine planets and nine gems, as shown below. Sometimes jewelry is made using one each of these gems. These are termed navaratna jewels (nava = nine; ratna = jewel).

Birthstones for days of the week

Another method of choosing a birthstone is according to the day of the week upon which one is born. In his book The Curious Lore of Precious Stones, George Kunz notes that specific gemstones are also associated with the day of the week you were born. These are listed below, along with alternatives of comparable hue for the more unusual gemstones.

The week is a division of time equal to seven days. We do not know exactly where it comes from, but the ancient Hebrews were among the first to use it. The book of Genesis in the Bible says that the world was created in six days and the seventh day, or Sabbath, was a day of rest and worship.

Ancient Egyptians named the days after planets, which they incorrectly believed included the sun and the moon. The seventh day was considered merely a day of rest and play. In ancient Rome, the days of the week were named after the sun, the moon, and the five planets then known. Each day was considered sacred to the Roman god associated with that planet. The days were known as Sun’s-day, Moon’s-day, Mars’-day, and so on. This system was used about the beginning of the Christian Era. The English names for the days Tuesday, Wednesday, Thursday, and Friday were derived from the names of Norse gods.

Most Latin-based languages connect each day of the week with one of the seven “planets” of the ancient times: Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn. French, for example, uses the following:

Gems for all seasons

One can also select gems by the season, as follows:

Of course, many countries do not have four seasons (Thailand, etc.), but we won’t get into that.

Choosing a birthstone

If nothing else, the above should make clear that there are a bewildering variety of birthstone choices, depending on nationality, culture, religion, etc. Which one is right for you? We suggest that, if none of the above birthstones strikes your fancy, you simply choose a personal gemstone that symbolizes a special time for you. Choose a personal gemstone based on your zodiac sign, the day of the week on which you were born or the color designated for your birth month.

Notes on Calendars

Before the invention of the clock, people watched the sun, moon and stars to tell time. The daily rising of the sun provided a short unit of time, the solar day. The cycle of seasons roughly indicated a longer unit of time, the solar year. But early people did not know that the earth’s revolution around the sun caused the different seasons. The changing position and shape of the moon was easier for them to observe. As a result, early calendars used the interval between the successive full moons, called the lunar month, as an intermediate unit of time.

Did you know?

Today we know the lunar month lasts about 29 1/2 days. Twelve such months amount to about 354 days. This interval is almost 11 days shorter than the true solar year, which has 365 days, 5 hours, 48 minutes, and 46 seconds. But a year of 13 lunar months would equal about 383 1/2 days and would be more than 18 days longer than the solar year. The solar year, therefore, does not equal any whole number of lunar months.

Note that these numbers are averages. The actual length of a particular year may vary by several minutes due to the influence of the gravitational force from other planets. Similarly, the time between two new moons may vary by several hours due to a number of factors, including changes in the gravitational force from the sun, and the moon’s orbital inclination.

The discrepancy between whole lunar months and days in a solar year explains the confusion over calendar keeping during thousands of years. A calendar based on 12 lunar months becomes out of step with the seasons. Some people who used lunar calendars kept them roughly in step with the seasons by making some years 12 months long and other years 13 months long.

Early calendars usually represented some sort of compromise between the lunar and solar years. Some years lasted 12 months, and others lasted 13 months.

The Christian calendar (Gregorian calendar) is based on the motion of the earth around the sun, while the months have no connection with the motion of the moon.

On the other hand, the Islamic calendar is based on the motion of the moon, while the year has no connection with the motion of the earth around the sun.

Finally, the Jewish calendar combines both, in that its years are linked to the motion of the earth around the sun, and its months are linked to the motion of the moon.

Further reading

• Kunz, G.F. (1913) The Curious Lore of Precious Stones. J.D. Lippincott, 406 pp.
• Click on these links more information on the origin of calendars and days of the week