Gemology Certification Jewelry Design & Precious Metals 1 — Questions and Answers
Question 1: What does '18 karat' gold indicate about the metal's composition?
- 75% pure gold and 25% alloy metals (Correct answer)
- 18% pure gold and 82% alloy metals
- 90% pure gold and 10% alloy metals
- 100% pure gold with 18 parts per thousand fineness
Correct answer: 75% pure gold and 25% alloy metals
18 karat gold contains 18 parts gold out of 24 total parts, making it 75% pure gold (18/24 = 0.75), with the remaining 25% consisting of alloy metals such as copper, silver, or palladium.
Question 2: What is the primary advantage of using platinum over white gold for gem settings in fine jewelry?
- Platinum is denser, more durable, and hypoallergenic with no replating required (Correct answer)
- Platinum is less expensive and easier to work with
- Platinum has a higher melting point making stone setting safer
- Platinum provides a brighter white color due to its lower density
Correct answer: Platinum is denser, more durable, and hypoallergenic with no replating required
Platinum is naturally white, hypoallergenic, extremely dense and durable, and does not need rhodium plating to maintain its white color, unlike white gold which requires periodic replating.
Question 3: In jewelry, what does the term 'prong setting' describe?
- Metal claws that grip the girdle of a gemstone to hold it in place (Correct answer)
- A closed metal collar surrounding the entire base of a gemstone
- A setting where the gem sits in a channel between two metal rails
- A technique of hammering metal flush over the gem's girdle
Correct answer: Metal claws that grip the girdle of a gemstone to hold it in place
A prong (or claw) setting uses small metal projections — typically four or six — that are bent over the girdle of the stone to secure it while exposing the maximum amount of the gem to light.
Question 4: What is 'sterling silver' and what is its fineness mark?
- 92.5% pure silver alloyed with 7.5% copper, marked 925 (Correct answer)
- 95% pure silver alloyed with 5% copper, marked 950
- 100% pure silver, marked 999
- 80% pure silver alloyed with 20% copper, marked 800
Correct answer: 92.5% pure silver alloyed with 7.5% copper, marked 925
Sterling silver is a standard alloy of 92.5% pure silver and 7.5% other metals (usually copper), stamped with the hallmark '925' to indicate its fineness.
Question 5: What setting type completely surrounds the girdle of a gemstone with a continuous wall of metal?
- Bezel setting (Correct answer)
- Prong setting
- Pavé setting
- Tension setting
Correct answer: Bezel setting
A bezel setting encircles the entire girdle of the gemstone with a custom-fitted metal collar, offering strong protection for the stone's edges and a sleek, modern appearance.
Question 6: What does the hallmark 'PT950' on a piece of jewelry indicate?
- 950 parts per thousand (95%) pure platinum (Correct answer)
- 950 parts per thousand pure palladium
- Gold plated to a thickness of 950 microns
- Sterling silver with 950 fineness
Correct answer: 950 parts per thousand (95%) pure platinum
PT950 is a hallmark indicating that the metal is platinum with a purity of 950 parts per thousand (95%), the most common purity standard for platinum jewelry sold in the US.
Gemology Certification Jewelry Design & Precious Metals 1
What does '18 karat' gold indicate about the metal's composition?