Onyx's streak is white.
white
white...
Onyx is a black volcanic gem that is commonly worn in jewelry. The value of onyx is determined by the quality and size of the stone. Onyx stones can sell for tens or hundreds of dollars.
Onyx rings are rings which are crafted from various metals including gold, white gold, silver, bronze and others. Then the stone which is chosen will be onyx.
Super value le
Onyx is a form or silicon dioxide (SiO2), and it is a "flavor" of quartz. It has a Mohs scale hardness of 7, and it is naturally brittle, like other forms of quartz. The hardness contributes to its strength, but it is at the same time a source of its weakness as brittle materials are subject to breakage. It can be worked and will take a high polish because it is quite hard. A link can be found below.
The natural colors of true onyx are usually red or brown with white, although black is occasionally encountered as one of the colors.Since onyx itself is a type of translucent/transparent milky or grayish quartz.Think of onyx as a grey or dark cream.
Best guess is $600 to $1000 depending on condition. I suggest you take it to a local gunsmith for appraisal and pay him for his time.
bout $20
Like onyx stunnishing light.
About $100.