Based on the word "topaz", the extra "z" makes this flexible domain stand out from the crowd.
Topazz has only six letters and only two syllables. Two-syllable names are highly rare and exceptionally valued. Examples of popular two syllable names include Visa, Apple and Subway.
This domain was first registered in January 2002. Older domains have an advantage when ranking in search engines.
Topazz.com is a dot-com domain. Dot com domains are the most sought after top-level-domain in the world, used by famous websites like twitter.com. Once secured, a dot-com all but guarantees no-one else can outrank you for your own name in the long run.