· birthstones
· stone chart
· moh’s hardness scale

[ birthstones ]

month	birthstone
January	Garnet, Rose Quartz
February	Amethyst, Onyx
March	Aquamarine, Bloodstone
April	Diamond, Rock Crystal
May	Emerald, Chrysophrase
June	Pearl, Moonstone, Alexandrite
July	Ruby, Carnelian
August	Peridot, Sardonyx
September	Sapphire
October	Opal, Tourmaline
November	Topaz, Citrine, Tiger's Eye
December	Zircon, Turquoise

[ stone chart ]
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stone	birthstone	moh's hardness	appearance
Alexandrite	June	8.5	Named after the Russian Czar, Alexander II, alexandrite is the gemstone most noted for it's color changing abilities. Colors are greenish outdoors, and reddish to violet under artificial light. Alexandrite is extremely rare. Look out for alexandrite which is too clean, or at a price which seems too low, it's probably synthetic. Natural alexandrite rarely exceeds 2 carats. Can be confused with synthetic alexandrite, or synthetic color change corundum. Pearl, moonstone and alexandrite are the birthstones of the month of June.
Amethyst	February	7	Violet, lilac or mauve quartz is called amethyst. Amethyst is sometimes heat treated to form citrine. Amethyst crystals can form together with citrine crystals to form bi-colored quartz called Ametrine. Amethyst is the birthstone of the month of February. Apatite N/A 5 Can be transparent to opaque, with colors ranging from yellow, green, blue, violet and colorless. Aquamarine March 7.5 - 8.0 Aquamarine is the blue, or blue-green type of beryl. Aquamarine and Bloodstone are the birthstones of the month of March. Featured here are some specimens of "Colonel Murta" aquamarine, which is the darkest aquamarine found anywhere in the world.
Bloodstone	March	6.5 - 7.0	This form of chalcedony appears as an opaque dark green stone with red spots, also known as bloodstone, and bluestone. The red spots were once thought during the Middle Ages to be drops of Christ's blood, and that the stone held special powers. Bloodstone is found in India, China, Brazil, Australia and the United States. Aquamarine and Bloodstone are the birthstones of the month of March. Hematite is also called "bloodstone".
Carnelian	July	6.5 - 7.0	Cornelian, also spelled Carnelian ranges in color from light brownish-red to deep transparent red. The color is due to Iron.
Chrysophrase	May	6.5 - 7.0	Chrysophrase, the most valued of the chalcedony, this translucent bluish green stone derives it's color from the presence of Nickel.
Citrine	November	7	Yellow or golden yellow quartz is called citrine. Citrine crystals can form together with amethyst or smoky quartz to form ametrine and bi-colored quartz. Citrine and topaz are the birthstones of the month of November.
Diamond	April	10	Diamond is occasionally laser drilled to improve appearance. Surface cavities or fractures are occasionally filled with a hardened surface. Colored diamonds are occasionally irradiated and/or heat treated to induce "fancy" colors.
Emerald	May	7.5 - 8.0	Emerald refers to the green variety of beryl. There are however, gem quality green beryls which are not emeralds. All emeralds contain inclusions, which are evidence as to the genuineness of the stone. The name is derived from the Greek word Smaragdos, meaning "green stone". Emerald is the birthstone of the month of May.
Garnet	January	7.0 - 7.5	Garnet is the name which can be applied to six similar mineral species, namely almandine, pyrope, spessartine, grossular, andradite and uvarovite. To further complicate matters, many garnets are actually a combination of these minerals. Rhodolite garnet for instance, is a combination of almandine and pyrope, and is sometimes referred to as pyrope-almandine garnet. There are also many trade names and other commonly used names which only adds to the confusion, such as Rhodolite, Tsavorite, Hessonite, Malaya, Mozambique, Mandarin, Ant-hill, Leuco, Hydrogrossular, Demantoid, Melanite, Topazolite, Thai. Other names such as "cape ruby" are simply misleading and deceptive. Some garnets also exhibit color change and stars.
Iolite	N/A	7.0 - 7.5	Has stong pleochroism, meaning the gemstone changes colors depending which angle it is viewed from. Cordierite displays colors ranging from deep blue, to violet and light blue and grayish blue. It can be confused with tanzanite (zoisite) which is also strongly pleochroic.
Labradorite	N/A	6	Can be red, orange, yellow, colorless, with a bluish play of color, "schiller". Spectrolite is the name for the Finnish labradorite.
Moonstone	June	6	Moonstone is opalescent, with a blue or white scheen, sometimes called "schiller", resembling moonshine. Composed of albite and orthoclase feldspar, the albite gives it the bluish color. Pearl, moonstone and alexandrite are the birthstones of the month of June.
Onyx	February	6.5 - 7.5	Onyx is the name given to chalcedony which is uniform in color, generally black or white. Onyx should not be confused with onyx marble, a banded stone which is a form of limestone (calcite or aragonite).
Opal	October	5.5 - 6.5	Iridescent, and opalescent with a wide range of internal colors.
Pearl	June	2.5 - 4.5	Pearls may be round, pear-shaped, button-shaped, or irregular (baroque) and are valued in that order. Pearls found attached to the inner surface of the shell are known as blister pearls. The best pearls are usually white, sometimes with a creamy or pinkish tinge, but may be tinted with yellow, green, blue, brown, or black. Black pearls, because of their rarity, are often highly valued. The unique luster, or orient, of pearls depends upon the reflection and refraction of light from the translucent layers and is finer in proportion as the layers are thinner and more numerous. The iridescence which some pearls display is caused by the overlapping of successive layers, which breaks up light falling on the surface. Pearls are not cut or polished like other gems. They are very soft and are injured by acids and heat; as organic products, they are subject to decay. Commercially valuable pearls are obtained from the pearl oyster (especially of the genus Pinctata) and from the freshwater pearl mussel (genus Unio). The largest natural pearl center is the Persian Gulf, which is said to produce the finest saltwater pearls. Other important sources are the coasts of India, China, Japan, Australia, the Sulu Archipelago, various Pacific islands, Venezuela, and Central America, and the rivers of Europe and North America. In ancient times the Red Sea was an important source. Nearly all of the world’s supply of cultured pearls is produced by the Japanese, who have perfected the techniques of pearl cultivation. Pearls are commonly produced by placing a small mother-of-pearl bead enclosed in a piece of mantle tissue in the body of the oyster. The oysters are then placed in cages that are suspended into sheltered bays for the period of time (up to 4 years) required for pearl formation.
Peridot	August	6.5 - 7.0	Olive green to yellowish green. The darker green is known as peridot, the yellower type chrysolite. Peridot and sardonyx are the birthstones of the month of August
Rock Crystal	April	7	Rock crystal is the name given to all clear colorless quartz. It is widely used as a popular ornamental stone and is also used as a gemstone. Although it is one of the least expensive gemstones, cut rock crystal has been used as imitation diamonds. Rock crystal lacks the fire, color (of course) and the rarity to be ranked as a fine precious gemstone. None-the-less, rock crystal is in wide use as a gemstone due to its beauty, affordability, availability and ease of cutting.
Rose Quartz	January	7	The soft pink variety of quartz, generally cloudy, or milky in appearance due to minute inclusions of foreign substances. It's somewhat more rare than other varieties of quartz.
Ruby	July	9	Named for it's color (Latin Rubeus). Ruby has been confused with red spinel and garnet. The color can range from "pigeon-blood" to brownish. Other colors are known as sapphire. Inclusions are common, and are used to tell the difference between a synthetic and natural stone. Ruby is the birthstone of the month of July.
Sapphire	September	9	Sapphires are found in a variety of colors. The reddish colors are called ruby. People generally think of sapphires as blue in color, although they are also colorless, pink, orange, green, golden, yellow, purple and black. Sapphire is the birthstone of the month of September. Red sapphires are known as ruby, and pinkish orange sapphire as padparadscha.
Sardonyx	August	6.5 - 7.0	Bands of sard (brownish red) and onyx (white), occasionally with agate (translucent). Peridot and sardonyx are the birthstones of the month of August.
Smoky Quartz	N/A	7	Smoky quartz is the dark brown variety of quartz. In the past, these were often sold as "smoky topaz". There is no such gemstone known as smoky topaz and it's illegal to refer to quartz as "topaz". Watch out for some unscrupulous dealers who sell "smoky topaz", it is probably quartz. Citrine was often passed off as topaz as well. Smoky quartz crystals can form together with citrine crystals to form bi-colored quartz. Smoky quartz is sometimes found rutilated, which would be called Smoky Sagenite (Rutilated Quartz).
Tiger's Eye	November	7	Chatoyancy, appearing in these varieties of quartz, is caused by fibrous inclusions. They are generally cut en cabochon, but is often cut into round pieces for necklaces and pendants. Tiger's-eye is also used for carvings, boxes, ashtrays and other similar pieces. When the color is a greenish grey, they are called cat's-eye quartz. A golden yellow reflection on a brown stone is called tiger's-eye. If the stone is blue-grey or bluish, it's colored by crocidolite, and is known as hawk's-eye. A darker brown, or mahogany-colored stone is known as bull's-eye or ox-eye.
Topaz	November	8	Yellow topaz is sometimes called "precious topaz" to distinguish it from the names "gold" and "madeiria topaz", which are in fact citrine (quartz). Yellow topaz is sometimes heat treated to make it look pink. The term "imperial topaz" is used by ethical jewelers to refer to topaz that is reddish orange of medium tone and higher saturation.
Tourmaline	October	7	There are more colors of tourmaline than any other known gemstone. The lighter colored stones are more valuable.
Turquoise	December	5.0 - 6.0	Sky blue to bluish green. The name means "Turkish stone". Turquoise is porous, so contact with liquids, oils or even perspiration should be avoided. Jewelry made with turquoise should be removed before washing hands, etc.. The pure blue color is rare, most stones contain the matrix from which it was found. Although the stones without matrix are rarer and more valuable, many people find the black matrix attractive, and makes the stone unique.
Zircon	December	7.5	Zircon, a naturally occurring gemstone, has colorless, yellow, orange, red, blue, brown and green varieties. Zircon, by it's name, is sometimes confused with cubic zirconia ("CZ"), which is synthetic. In addition, both have been used as diamond substitutes. Zircon has a high refractive index which is responsible for it's diamond like appearance. Zircon can be distinguished from diamond by it's double refraction and by wear and tear of it's edges, as compared to diamond which is very much harder.

[ moh’s hardness scale ]
In 1822, a German Mineralogist, Friedrich Moh, developed a hardness scale. While not scientifically based on the true numerical hardness of gemstones, it is so practical in its application, it's still in use today by most Geologists and Gemologists.

Some things should be said first--some stones/gems are harder in one direction than the other. For instance, Calcite is easily scratched with a nail in one direction (Hardness 2), but difficult to scratch in another direction (Hardness 3).

Some handy points of reference are: a fingernail, about 2 -2 1/2. A copper penny is about a Hardness of 3, a steel knife, a bit over 5 and glass about 5 1/2. Really good steel runs about 6 1/2.

hardness	key stone	comments
10	Diamond	Hardest mineral known to man
9	Corundum (Sapphire/Ruby)	Harder than Topaz
8	Topaz	Harder than Quartz
7	Quartz	Scratches Glass
6	Microcline	Suitable for gems
5	Apatite	About the hardness of teeth
4	Fluorite	Cannot be scratched with a nail
3	Calcite	Difficult to scratch with a nail
2	Gypsum	Easily scratched with nail
1	Talc	Very soft, chalk-like