Gem of the Month
Each month this section will feature
either a topic of interest to gem lovers or one special gemstone with
background on the material and its value.
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October, 2003
Rose Quartz
Pale to light to medium dark pink,
slightly to moderately hazy crystalline or massive quartz is called
rose quartz. It has long been a favorite for beads, carvings, art
objects and jewelry. No other gem has quite the same look of
silvery-pink mistiness. All quartzes are widely distributed, but rose
quartz is less common than most and generally doesn't occur in as
large sizes as many of the other varieties do. The slightly to
moderately translucent, hazy interior is caused by discontinuities of
the crystal structure which make this variety slightly more brittle
than others, but still tough enough for most jewelry uses. When
minute rutile needles are distributed as inclusions "asterism"
results producing star rose quartz.
The pink color has two possible
sources: usually it is quite stable and due to titanium impurities,
but there is a less common and less stable type which is thought to
be due to phosphorus color centers which can fade slightly with
extreme light or heat. Of all the forms of crystalline quartz, rose
quartz shows the greatest degree of dichroism, often a surprising
amount considering its generally pale color.
The highest quality material is mined
in Madagascar, but the greatest volume comes from Brazil. There are
also significant deposits in the US, Japan, Namibia and Russia. The
highest yielding geological formations are pegmatites and
hydrothermal veins.
The rose quartz found in today's
marketplace has occasionally been enhanced by irradiation to produce
darker colors -- this treatment is undetectable and stable, and
therefore tolerated as "standard" in the marketplace. You can avoid
the treated ones, in general, by sticking with the traditional paler
colors. Glass imitations exist, but are easily detected by their
clarity and the presence, within, of swirls and bubbles.
Value Considerations
Beyond having at least visible pink
color and not being too cloudy, most of the value associated with
rose quartz pieces comes from the artistry of the fashioning--this is
generally true of modestly priced lapidary materials. An exception to
this would be star stones which have enhanced value due to the star
phenomenon.
Gemological Properties:
Chemical Composition: Silicon Dioxide
(SiO2)
Crystal System: Hexagonal
RI: 1.54 - 1.55
Density: 2.65
DR: .009
Dispersion: .013
Pleochroism: moderate to strong in
shades of pink
Cleavage: none
Luster: Vitreous
Fracture: Conchoidal
Hardness: 7
Toughness: Good
Stones Currently Available:
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our Catalog}
Go to: Homepage
-- what's new in faceted
gems -- what's new in
designer cabochons and gem carvings --
gem of the month --
gem of the month archive --
birthstone of the month --
key to all the codes used on the ACS
site -- definitions of
terms used on the ACS site
-- how to order
-- about ACS --
about the ACS cutters --
settings for these gems
--faceting information
-- purchase UltraTec
equipment
-- Mail to
bsmigel@cox.net