Although Brazil supplies the finest aquamarine and Colombia the finest emerald, several localities in the United States are sources of good-quality beryl of these colors. Foremost among these localities are Maine, California, and Connecticut for aquamarine and North Carolina for emerald. Morganite of pale pink to deep peach color, from California, is also notable. Various New England mines in Maine, New Hampshire, and Connecticut and the gem mines of the Pala and Mesa Grande districts of California have produced other colors of gem beryl. However, most of the beryl mined in the United States is used as an ore for beryllium, as little of it is of gem quality.
Because of its hardness (about 8), vitreous luster, beautiful color, and rarity, emerald always has been highly prized as a gem. Fine-quality emeralds may be more costly than fine diamonds. Other kinds of beryl have the same physical properties as emerald, but since they are less rare their relative value is lower.
Synthetic emerald of high gem quality has been marketed successfully. A synthetic substitute for aquamarine is also available; it is really a synthetic blue spinel.
VARIETIES Emerald: Grass green Aquamarine: Blue green Morganite: Pink Heliodor: Yellow Goshenite: Colorless
TOPAZ
Three different cutting styles and colors of topaz. From top, a 235-carat colorless stone from Colorado, a 171-carat dark champagne-colored stone from Madagascar, and a 129-carat sherry-colored stone from Brazil. (Slightly less than actual size.)
Because yellow is the most popular color of topaz it has become customary to believe that all topaz is yellow. Also, there is a tendency to believe that all yellow gemstones are topaz. Neither belief is correct. Stones of yellow, sherry, blue, pink, and colorless topaz all make beautiful gems, and their characteristics are identical except for color. On the other hand, citrine (a yellow quartz), although entirely unrelated to topaz, often is disguised in the trade under the names Brazilian topaz, topaz quartz, or just topaz. Great numbers of stones described and sold as yellow topaz really are the much commoner citrine, which has few of the characteristics of fine topaz.
A cushion-cut topaz from Brazil that weighs 1469 carats. It is an odd shade of yellow-green.