Quartz veins with nice yellow to orange color was found in northern
Minas Gerais in Brazil in July 2006 . Gemstones cut from this quartz are
sold under the trade name of Sunset Quartz. Its unusual color is caused
by abundant presence of tiny needles to several mm long of an unknown mineral,
probably of the family of hornblende. Sunset Quartz is quite similar to
Fire Opal, because the diffused small inclusions gives a nice Tyndall Effect,
as in opalescence. The advantage is that quartz is much more resistent
for jewelry purpose.
The discovery was done by dealer and prospector Jean-Claude Nydegger,
in northern Minas Gerais in Brazil. Just 5 kg of rough was produced the
first year and just small stones has been cut, beig the biggest one of
Most of the rough is eated at 350°C and an irreversible orange
coloration appeared. The rough has many colored portions, but its color
is strongly variable and for that reason it is better apply the eat treatment
process. The eat treatment helps to have a more uniform coloration.