Pages

Friday, July 24, 2009

Vermont "Grossular Garnet" !


Vermont's Legislature designated the grossular Garnet as it's official state gem in 1991.
.
Grossular or grossularite is a calcium-aluminium species of the Garnet group though the calcium may in part be replaced by ferrous iron and the aluminium by ferric iron. The name grossular is derived from the botanical name for the gooseberry, grossularia, in reference to the light green Garnet of this composition. Other shades include cinnamon brown (cinnamon stone variety), red, and yellow. The more common variety of grossular Garnets are called hessonite from the Greek meaning inferior, because of its inferior hardness to Zircon, which the yellow crystals resemble. Grossular Garnets, like other Garnets, form rounded crystals with 12 rhombic or 24 trapezoidal faces or combinations of these and some other forms. This crystal habit is classic for the Garnet. As stated, Grossular is the calcium aluminum Garnet and forms in contact or regional metamorphic enviroments as does andradite Garnet, the calcium iron Garnet. It is believed that these Garnets form from the metamorphism of impure siliceous limestones. Grossular has many color possibilities and is probably the most colorful of the Garnets. The orange variety is the most common and specimens of orange grossular crusts are prized by many collectors. The dark green variety is called tsavorite and is cut as a gem. Hessonite is a red to yellow variety of grossular and is also used as a gem.
.
Windom and Lamoille counties are the primary locations for Garnets in Vermont, but collectors are reminded to obtain written permission to search for them on priviate property or old mine sites. Beautiful brownish-reddish grossular Garnets can be found near Mt. Belvidere, Eden Mills, Vermont.
.
.