Topaz
Information
Most topaz is light brown when mined and then turns
colourless after exposure to light or low heat. Yellow, orange and
pink topaz are highly regarded. Good brilliance and hardness also
add to their value. High quality, yellow-orange topaz may cost
several hundred dollars per carat whereas citrine quartz of similar
colour and quality may sell for less than $35 a carat. Due to the
price difference, some sellers call citrine quartz, which is widely
available, “quartz topaz” or even “topaz” to make it sound more
expensive. Prior to the 18th century, all yellow stones
and some green ones were usually called “Topaz.” Even today, some
miners refer to almost any yellow stone as a topaz. Therefore, when
buying topaz, ask the seller to specify on the receipt that it is
genuine topaz and not quartz or another gemstone.
Natural pink topaz is the most valuable of all and the more
intense colours demand the higher prices
The richer blue topaz is produced by irradiating and then
heating certain colourless material. Green topaz does not occur
naturally and is diffusion treated.
| RI: 1.61-1.64 |
SG:
3.50-3.57 |
Hardness:
8 |
Toughness: Poor |
| Treatments:
Blue is usually heated and irradiated, pink & red
is usually heated; green is diffusion treated |
| Care Tips:
Avoid ultrasonic cleaners, steamers, rough handling, and
rapid cooling or heating |
Value: Imperial
topaz from $200 to $2000 USD per carat
Blue topaz up
to $20 USD per carat (Newman, 2003) |
Topaz can be securely purchased on this
web site at bargain prices ... see
here
|
