Imperial - Top Color: oR, R 5/5
Blues & Colorless - Top Color: vslgB, gB 5/5
Accompanying value information:
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
The highest values go to the rare pink and red stones, then orange and yellow. Intense, reddish orange topaz is sometimes called “imperial topaz.” Yellow, orange, and brown stones are somewhat common. Colorless topazes are common and are low-value gems in any size.
The term “precious topaz” refers to stones with a rich yellow to a medium, peachy orange color.
Blue has become the most popular color for topazes on the market today. However, almost all such gems began as colorless or pale blue topazes. A safe and very common heat-and-radiation treatment gives them striking, darker colors. Blue topazes are very inexpensive.