Colored Stones Chapter 10
Tiny nicks and pits caused by wear and damage to a gem's facet edges or culet is
Abrasions
A damaged area on a gem, usually near the girdle is a
Chip
Any hazy or milky area that cannot be described as a feather, fingerprint , or group of included crystals or needles is a
Cloud
Description for a gem with no inclusions visible to the unaided eye is
Eye Clean
a general term for break in a stone
Feather
Inclusions that form a pattern that often resembles a human fingerprint is a
Finger Print
A mineral crystal trapped within a gem as it grows is a(an)
Included Crystal
A long, thin inclusion that can be a solid crystal or a hollow tube that might be filled with liquid or gas is a
Needle
an angular, hollow peace within a gem that resembles a mineral inclusion
Negative Crystal
Minute inclusion enclosed within a gem; can occur singly or in groups called clouds, is a
Pinpoint
Tiny, parallel grooves on a facet surface left by the polishing operation are
Polish Line
Contrast between an inclusion and its host gem is
Relief
A linear scrape, normally seen as a fine, curved or straight, white line is a
Scratch
Group of fine needle-like inclusions is
Silk
What kinds of clarity characteristics have most influence on value
Those that affect transparency, brilliance, or durability
Aquamarine; pink, green, and yellow beryl; chrysobery (excluding cat's-eye; spodumene; green tourmaline; blue zircon; and tanzanite are what type of stones?
Type 1
Andalusite, alexandrite, corundum (excluding stars), the transparent garnets, iolite, peridot, spinel, quartz, all colors of tourmaline except green and water-melon, and zircon are what time of stones?
Type 2`
Emerald, red beryl, and water-melon tourmaline are what type of stones?
Type 3
the term silk describes
a group of fine, needle like inclusions
name a clarity characteristic that would have the greatest impact on a gem's marketability
a large, unhealed feather
example of a type III
emerald
the highest clarity grade for a colored stone is
eye clean
a general term for a break in a stone
feather
inclusions are important to gemologists because they can
help separate natural from synthetic gems
in which of the following colored stone clarity grades do the definitions vary for each clarity type?
moderately included
an angular, hollow space that resembles a mineral inclusion is called a
negative crystal
fingerprints are
partially healed fracture planes
2 factors that help determine an inclusion's impact on a gem's value are
position and relief
gems that are eye-clean include
spodumene, yellow beryl, and aquamarine
in which colored stone clarity type are the gems usually eye clean?
type I
an inclusion with the most negative impact on a colored stone's clarity would be located
under the table
Characteristic or irregularity confined to the surface of a polished gemstone
Blemish
An opening that extends into a gem from the surface is a
Cavity
a characteristic of irregularity confined to the surface of a polished gemstone is a(n)
blemish
growth zoning in a colored stone is evidence of
crystal growth
