John Anthony Jewelers

Main Line Philadelphia GIA Report Diamonds and Fine Jewelry

133 Montgomery Avenue
Bala-Cynwyd, PA 19004-2828
Phone: (610)-664-8777
Click Here for Store Hours


Some of the most popular Gems used as birthstones and in jewelry are as follow.

January Birthstone: Garnet
Colors: Found in every color of the rainbow except blue
Main Varieties:
Almandite: reddish orange to purplish red
Andradite: (Demantoid) (bright yellow - green)
Malaya: reddish orange
Rhodolite: purplish red through reddish purple
Pyrope: reddish orange to purplish red
Grossularite: (Tsavorite) bright yellow green to grass green
Source: Africa, India, Sri Lanka, Brazil, and USA
Hardness: 7-7 1/2
Durability: Durable for all kinds of jewelry

February Birthstone: Amethyst
Colors: From pale lilac to deep purple
(Deepest colors are the most valuable)
Sources: Brazil is the most prevalent source
Hardness: 7
Durability: Durable for all kinds of jewelry
Comment: Some amethyst crystals are heat-treated to change their color to yellow, producing citrine (see gems of color).

March Birthstone: Aquamarine
Colors: Slightly grayish light blue to medium blue green
(Pale in tone). The darker the color the better.
Sources: Brazil and Africa
Hardness: 7 1/2 to 8
Durability: Durable for some types of jewelry

April Birthstone: Diamond
Information: See Diamond Information
Sources: Africa, India, Russia, Australia, Canada and USA
Hardness: 10
Durability: Excellent for all types of jewelry

May Birthstone: Emerald
Colors: Very light to very dark green
(Yellow or blue modifying colors)
Sources: Brazil, Columbia, Africa (Zambia)
Hardness: 7
Durability: Can be fragile
Comment: In ancient times, most emeralds came from Cleopatra's mines in Egypt, which now yield only low-quality emeralds.

June Birthstones: Pearl
Information: See Pearl Information
Sources: Japan, China, South Pacific
Hardness: 3
Comments: Pearls are sensitive to acids, dryness, and humidity, and so are less durable than many other gems.

Color: Changes from green (daylight) to purplish red (artificial light)
Sources: Ural Mountains, Russia and Brazil
Hardness: 8
Durability: Durable for some types of jewelry
Comments: Alexandrite is very rarely seen in sizes over 1 ct.

July Birthstone: Ruby
Color: Medium to dark red
Source: Burma, Thailand
Largest gem-quality crystals are from Myanmar
Hardness: 9
Durability: Excellent durability for all types of jewelry

August Birthstone: Peridot
Colors: Light yellow green to dark olive green
Sources: Sri Lanka, Burma, USA (Arizona), Pakistan
Hardness: 6 1/2 to 7
Durability: Good for most types of jewelry

September Birthstone: Sapphire
Colors: Sapphires come in every color of the rainbow except Red (Ruby)
Sources: Sri Lanka, Thailand, Australia, and USA (Montana)
Hardness: 9
Durability: Excellent Durability for all types of jewelry

October Birthstones: Opal
Color: Play of color is the opal's ability to display many colors. All colors can occur in opals. Pattern of Play of color also helps determine the value of the opal.
Broad flash: larger areas of color are more valuable
Harlequin: an opal with all broad flashes of color
Types: Black: dark (dark gray to black) bodycolor
Crystal: transparent with flashes of color
Milky: most common, milky white bodycolor
Fire: faceted stone named after its orange bodycolor
Sources: Australia, Mexico, Brazil, and USA
Hardness: 5 - 6 1/2
Durability: Opals are very fragile

Colors: Occurs in every color of the rainbow
occurs in two and three color combinations (bi and tri-color)
Sources: Brazil, Africa, Sri Lanka, California, Maine
Hardness: 7 - 7 1/2
Durability: Durable for some types of jewelry

November Birthstone: Topaz
Colors: Orange, yellow, pink, brown, and blue
London: dark grayish light blue
Swiss: neon light blue
Sources: Brazil, Sri Lanka
Hardness: 7 - 7 1/2
Durability: Durable for some types of jewelry
Comments: Natural pink topaz is rare; most pink topaz is the result of heat treatments on yellow stones.

December Birthstone: Blue Zircon
Color: Blue (common) also found in red, orange, brown, yellow, and green
Sources: Thailand, Cambodia, Vietnam, Brazil
Hardness: 7 1/2
Durability: Good for some jewelry use
Comments: Zircon is an attractive stone when set in a ring; however care must be taken with these as cut stones can be damaged.