Greenlandite
Greenlandite was discovered in the 1960s
during the survey of the large iron deposit, Isukasia north
of Nuuk. Greenlandite was subsequently discovered in
several localities in the Godhabsfjord area. It was
later established that the geological environment in which
greenlandite was formed was in the order of 3.8 billion years
old. this means that we are talking about one of the earths
oldest formations
Geologically speaking, the rock consist of
quartzite with a large content of a green minerals - fuchsite
- evenly distributed throughout, giving the stone a fresh
green color. Quartzite is made of fine-grained quartz,
while the chromium-containing fuchsite resembles glitter,
with fine spangles distributed throughout the rock.
Greenlandite is a hard mineral, often translucent with a metallic
inner glow derived from its many spangles. this type of stone
is also known, in the jewelry trade, as aventurine quartz.
Greenlandite has been used as a gemstone
in Greenland for many years, justly marketed as “the
world’s oldest gemstone”. Green aventurine quartz
has long been known as an Indian or Brazilian gemstone, and
more recently stones from southern Africa have appeared which
can be difficult to distinguish from greenlandite. Experts
will note that the color of greenlandite is a more bluish
green than that of the foreign variants of aventurine quartz.
Any confusion with jade (nephrite) (hardness H=6) can be resolved
with a hardness test.
Composition
 Greenlandites’
two components are quartz (SiO2) with a hardness of H=7 and
fuchsite (K(Al,Cr)2AlSi3)10(OH,F)2) with a hardness of H=2.5.
As a result the stone is very hard and can readily be polished
to a smooth surface. Varying green (fuchsite) and white
(quartz) schlieren (streaks) in the same piece can produce
many variants of the stone. That indeed is part of greenlandites’
singularity.
Gemstone
 For
lapidary purposes the most usual form is as a cabochon, but
flat polishing also produces pleasing effects. Thin slices
are partially translucent, and are therefore well-suited to
uses where light can shine through them. Polished greenlandite
is best suited to mounting in silver. Superb results have
been obtained by mounting in combination with other single-colored
gemstones, such as red tugtupite, or blue lapis lazuli.
Greenlandite is well suited to carving for
signet rings, for example. the best-known use of greenlandite
is in fact in the Bishop of Greenland’s cape.
Larger pieces can be used decoratively as bookends or letter
racks. It is also well-suited for use in larger stone arrangements,
mosaics, and candle holders.
MinerShop stocks an inventory
of this and other Gem Rough. Contact
sales for availability and prices. |
