GIA's color-grading scale for diamonds is the industry standard. The scale begins with the letter D, representing colorless, and continues with increasing presence of color to the letter Z, or light yellow or brown.
Hallmark(s): "Zina" Information: Zina Sterling Silver was founded in 1983 by silversmith, Zina Sherman. Works primarily in silver. Zina.
925 markings on jewelry pieces mean that the pieces are sterling silver. 925 markings on jewelry are a universal standard used to indicate the purity of silver. The jewelry number 925 is significant because it means that the jewelry piece is made of 92.5% silver and 7.5% other metals.
Gold Purity Marks
The letter “k” refers to karats, where pure gold is composed of 24 karats (24k). A piece of jewelry with an etching that reads “18k” or “750” indicates that it is made up of 75 percent gold, while a “14k” or “585” mark indicates the metal is constructed with 58.5 percent gold.
Symbols with 900 indicate that there are 900 parts per 1,000 pure platinum; whereas symbols with 950 indicate that there are 950 parts per 1,000 are pure platinum. 10K, 14K, 18K, 24K... If you only see these stamps on your piece, it means that the piece is solid gold. The numbers denote the karat fineness of the gold.
Gold hallmarks measure purity
Gold purity is measured in karats with 24 karats representing the highest value. Gold jewelry marked "750" or "18k" indicates a blended metal consisting of 75% gold and 25% other alloys or elements. Likewise, a "585" or "14k" imprint indicates a gold content equal to 58.5% of the whole.
GIA's color-grading scale for diamonds is the industry standard. The scale begins with the letter D, representing colorless, and continues with increasing presence of color to the letter Z, or light yellow or brown.
Gold-plated pieces may be marked 'GP,' 'GE,' or 'HGE. ' 'GP' or 'GE' means the piece is electroplated with a thin layer of gold; '18K GP' would indicate a piece plated with 18 karat gold.
In this case the letter 'z' (2) indicates it was assayed in 1874. The date letter changes every year so you can precisely date the year it was made. The maker's mark (1) shows that it was made by Robert Thornton. The last mark (5) the Sovereign Head, in this case, is Queen Victoria, showing the duty has been paid.
(Fun fact: Real gold is not magnetic.) Fake gold, on the other hand, will stick to the magnet.
Cubic zirconia is classified as a diamond simulant - a stone that looks similar to natural diamonds, but is made of different material. Natural and lab-grown diamonds are made of carbon, while cubic zirconia is made of zirconium dioxide (ZrO2).
Zales. Your Online and Local Jewelry Store.
Cubic Zirconia, CZ, or C.Z., is the most successful diamond simulant.
Look for a Letter Mark
If the item of jewelry has the letters GP, GF, or GEP stamped on it, these indicate that it is not made of real gold. GP means it is gold plated, GF means it is gold filled, and GEP means it is gold electroplate.
Acid test.
An acid test can reveal the karat of solid gold jewelry, but it can also show whether jewelry is solid gold or gold-plated. With an acid test, a small sample of the jewelry is removed and exposed to acid to induce a color change. The resulting colors indicate which type of metal the jewelry is made of.
R = real numbers, Z = integers, N=natural numbers, Q = rational numbers, P = irrational numbers.
Ź (minuscule: ź) is a letter of the Latin alphabet, formed from Z with the addition of an acute accent. The letter appears in Polish, Montenegrin, Lower Sorbian, Upper Sorbian, Emiliano-Romagnolo, Wymysorys and Brahui, as well as in the Belarusian Latin alphabet, Ukrainian Latin alphabet and Romanized Pashto.
Louis Vuitton fine jewellery campaign featuring the brand's LV initials is blasted after social media users point out likeness to Russia's Z symbol of 'violence and death'
Use a Magnet
Using a magnet is a good way of identifying whether your jewelry is authentic or not. If your jewelry sticks to the magnet, it may be fake or not pure gold — this is because real gold is not magnetic at all, and even with a strong magnet it will not be attracted.
Gold metals are represented by an octagonal fineness shape. '375' is the mark for 9ct gold, which means it is 37.5% gold and 62.5% other alloys, '525' is the mark for 14ct gold meaning 52.5% is pure gold and 47.5% is other alloys and '750' is the mark of 18ct gold, meaning it is 75% pure gold and 25% other alloys.
Basically, gold won't react to nitric acid, but all other metals will turn greenish. Don't douse your jewelry in the acid—just put it in a stainless-steel dish and use a dropper to drop or Q-tip to test a tiny section. If your jewel doesn't react to the nitric acid, you have a real gold piece (14k or higher).