The field test for a diamond is 'extreme hardness'.
simulated diamond means that it has all the characteristics of a real diamond but is fake.
A certified diamond is one that has been evaluated by a professional in whatever certification method is documented by the certificate. For example, the Gemological Institute of America -- GIA -- certifies diamonds by documenting the colour, clarity, cut and carat weight of the diamond. This establishes the individual characteristics of the gem. A non-certified diamond can only be evaluated according to the expertise of the person evaluating the diamond, and usually without certification. It's characteristics, therefore, are uncertain.
A cut and polished, commercial diamond is valued by its cut, clarity, carat weight and colour. A real diamond conducts electricity, is the hardest mineral known and comes in many natural colours, depending on what other trace minerals are present in the stone.
That really depends on the exact pressure. Look at the Wikipedia article "Carbon#Characteristics" (article "Carbon" section "Characteristics"). Especially, take a look at the phase diagram.
Jewelers use a combination of methods to determine if a diamond is real. They typically examine the diamond under specialized lighting conditions to check for certain physical properties such as light reflection and refraction. They may also use magnification tools to examine the diamond for inclusions or other identifying characteristics. Additionally, some jewelers may use electronic diamond testers that measure thermal conductivity to quickly confirm the authenticity of a diamond.
simulated diamond means that it has all the characteristics of a real diamond but is fake.
Square and a Diamond
A red diamond will cost you more than a blue diamond, given that all other characteristics of the stones are equal.
A raw diamond has these geometric characteristics: its crystal habit is octahedral, and its crystal system is isometric-hexoctahedral (cubic).
A certified diamond is one that has been evaluated by a professional in whatever certification method is documented by the certificate. For example, the Gemological Institute of America -- GIA -- certifies diamonds by documenting the colour, clarity, cut and carat weight of the diamond. This establishes the individual characteristics of the gem. A non-certified diamond can only be evaluated according to the expertise of the person evaluating the diamond, and usually without certification. It's characteristics, therefore, are uncertain.
The ratings for diamonds are determined by 5 different things. The diamond cut, clarity, color, weight and finally the diamond certificate which lists all the unique individual characteristics.
Any diamond is 'good' when it can be certified as to its characteristics: cut, colour, carat weight and clarity. A certified gemologist can perform this work for you.
The grading report or the diamond certificate enlists the individual characteristics of a particular diamond stone. To ensure the genuineness of diamond jewelry, it is important to demand its grading report from the seller before buying.
If you are not a jeweler than the best way is to ask for gemological report at GIA, EGL, IGI. Which will confirm the origin of diamond and it's characteristics. For more information on synthetic diamond follow my link below.
Any diamond is worth whatever someone will pay you for it. You've only given two of the four characteristics used to value a diamond, lacking its cut and its carat weight.
The price of any diamond depends not only on its carat weight, but on its colour, clarity and cut. A local jeweler can show you a diamond of this carat weight and give you a price, depending on its other characteristics.
Whatever you have to sell is worth whatever someone will pay you for it. You can purchase a diamond with these characteristics today on Blue Nile and spend between US$13,884 and US$19,165, depending on the excellence of the cut and exact carat weight that you want. If you own a diamond of this quality, best practices dictate that you pay a certified gemologist to produce documentation of the diamond's characteristics. This will support your research in establishing a market value for the diamond.