Practice Test Geeks(CBJ) Certified Bench Jeweler Practice Test
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Gemstone and Setting Techniques Flashcards

6 cards from real CBJ practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 6 Gemstone and Setting Techniques flashcards as text

  1. What is the Mohs hardness rating of diamond?

    Answer: 10

    Diamond rates 10 on the Mohs hardness scale, making it the hardest known natural mineral.

  2. What Mohs hardness do sapphire and ruby share?

    Answer: 9

    Both sapphire and ruby are varieties of corundum with a Mohs hardness of 9, making them highly durable for everyday wear.

  3. What distinguishes a ruby from a blue sapphire at the chemical level?

    Answer: Chromium content causing red color vs. iron and titanium causing blue

    Both are corundum (Al₂O₃), but chromium traces cause rubies' red color while iron and titanium produce sapphires' blue color.

  4. What is the approximate Mohs hardness range of opal?

    Answer: 5.5–6.5

    Opal has a Mohs hardness of approximately 5.5–6.5, making it more fragile and prone to scratching than most popular gemstones.

  5. Which gemstone is famous for displaying asterism (a star effect)?

    Answer: Star sapphire

    Star sapphires display asterism—a star-shaped reflection—caused by intersecting needle-like rutile inclusions aligned within the crystal.

  6. What is the most common treatment applied to commercial sapphires to improve color and clarity?

    Answer: Heat treatment

    Heat treatment is the most widely used enhancement for sapphires, improving color saturation and dissolving silk inclusions.

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  1. jewelers.org — Test delivery, eligibility, fees, passing score, retake fee, retake policy, score release, time limit · verified Oct 2026