In “The Sign of Four” a box filled with jewels was sought by almost every major character in the novel. The Agra treasure consisted of 143 Diamonds, nearly 300 pearls, 97 emeralds, 170 rubies, 40 carbuncles, 210 sapphires, 61 agates, and beryls, onyxes, cat’s eyes, turquoises, and an unnumbered amount of other stones. They were probably all cut gems, except for the pearls.
The treasure was kept in a chest of Indian workmanship and of considerable weight. It had no key when the police recovered it from Jonathan Small. Dr. Watson had served in India during the Second Afghanistan War. He identified it as an example of Benares metal-work. Benares is a city in India situated on the holy river of the Ganges in the north-central part of the sub-continent. The chest had a thick and broad hasp, wrought in the image of a sitting Buddha. The box was massive, well-made and solid, clearly constructed to carry things of great price.
The walls, floor and lid of the container were two-third of an inch thick and made of iron. The actual size of the chest was not given. It was small enough that, while very heavy, Watson could carry it by himself.
This paper gives a short description of the four most valuable kinds of gems described by Small as being part of the Agra treasure contained in the box.
The “Great Mogul” diamond mentioned in the story actually existed. It was found in India in 1650 as a 787 carat rough stone. It was cut and described in 1665 as a high-crowned rose-cut stone. Its owner, Nadar Shah, King of Persia, was assassinated in 1747 and the stone disappeared. Some experts believe it may have been re-cut into either the Orlov Diamond of the Romanov Imperial Jewels or into the Koh-in-noor, now a part of the British Crown Jewels.
Diamonds were said in ancient times to assist the wearer’s stomach and brain. They were thought to strengthen the memory. Diamonds supposedly promoted purity, life, joy, innocence, repentance and honesty. The finest diamonds are a clear blue-white color but they can come in other hues, like yellow or pink.
Diamonds come from Africa, India, Russia, South America and even the United States.
Emeralds are a grass-green variety of beryl. They can be cut in rectangular, round, oval or square shapes. Some are shaped into cabochons. It is the birthstone of Taurus the Bull, April 20 to May 20. They are the gemstones of the 20th, 35th and 55th year of marriage. Ancient emeralds were found in Upper Egypt in 2000 B.C. They were highly prized by Alexander the Great and Cleopatra.
The Moguls, or rulers, of India inscribed sacred texts on large emeralds and wore them as talismans. For their size, emeralds can be more valuable than diamonds.
Emeralds supposedly had many virtues. They were used as antidotes to poison in the Middle Ages. The wearer of an emerald was said to gain wisdom, success in love and constancy of mind. Worn as an amulet, emeralds were thought to give good fortune, and symbolize rebirth and youth.
The Agra treasure emeralds could have come from the Urals, Africa or India itself.
Pearls come from mollusks like freshwater clams or saltwater oysters. They are formed by the mollusk coating a tiny bit of irritant like a grain of sand within the shell with mother-of-pearl, the substance the inner shell is made of. Irregularly-shaped pearls are called baroque pearls. Freshwater pearls have been found in the Mississippi River and in other freshwater creeks. Over a short period of time in the late 1800s three pearls were found in clams in Evansville, WI. Cultured freshwater pearls have been grown in the streams of Bavaria, Australia and the United States.
Man-made or cultured pearls have been made in China for over a thousand years. In the 1890s the Japanese began producing an improved cultured pearl.
Saltwater pearls are called Oriental pearls. They can be cultured or natural pearls. Natural pearls have been found in the Persian Gulf, the waters between India and Sri Lanka, Indonesia and the South Pacific. They have also been found in the ocean off Western Mexico.
Pearls can be cream-colored but also black, rose, gray, blue, yellow, lavender, green and mauve. Pearls are the birthstones of Gemini, May 21 to June 21. A pearl is said to symbolize love, success, and happiness. They are the gemstone for the 1st, 12th and 30th year of marriage.
Rubies are made of corundum, which produces both rubies and sapphires. Large, fine-quality rubies are rare and valuable. They may be cut into mixed-cut ovals or antique cushions if they are lighter-colored stones. Dark red rubies are made into cabochons or into beads. Only diamonds are harder gemstones.
The name ruby comes from the Latin “ruber” which means red. The best rubies are a deep, pure, vivid red. Gemologists must carefully tell the difference between pinkish, purplish or orangey red rubies and pink, purple or orange sapphires.
Rubies are the birthstone for Aries, March 21 to April 19. They supposedly signify primal energy, self-assertiveness, daring, initiative, enterprise and adventure.
During the Middle Ages, a ruby worn on the left hand was thought to bring its owner lands and titles, to bestow virtue and protect against seduction. They were thought to guarantee health, wealth, wisdom and success in love. Some people of India believed possessing a ruby would enable them to live in peace with their enemies.
Rubies are found in Afghanistan, Kenya, Madagascar, Burma, Sri Lanka and Thailand.
The Agra treasure box once held well over a thousand precious jewels. Yet it was more valuable when Dr. Watson and Mary Morstan discovered it was empty. With the gems gone the honest Doctor felt himself free of the taint of fortune hunting and allowed his love for Mary to express itself. Proverbs 31:10 says “Who can find a virtuous woman? For her price is far above rubies.” Watson agreed. After his declaration of devotion to the woman he loved was accepted, Watson wrote “Whoever had lost a treasure, I knew that night that I had gained one.”