Gemology MCQs Part 6

Test Your Knowledge in Gemology Part 6

1. A 2-carat fine-quality ruby is worth more than 10 rubies of the same color and quality, which have a total weight of 4 carats.

a) True
b) False

Correct Answer: a) True

2. One carat equals:

a) 1 gram
b) 1/10 of a gram
c) 1/5 of a gram
d) 1/2 of a gram

Correct Answer: c) 1/5 of a gram

3. A ten-pointer is a stone that weighs:

a) 10 carats
b) 1/10 of a carat
c) 10 facet junctions
d) 10 grams

Correct Answer: b) 1/10 of a carat

4. When comparing gem prices, you should compare their:

a) Per-carat cost
b) Overall size
c) Density
d) Facet count

Correct Answer: a) Per-carat cost

5. If a Tanzanite weighs 4 carats and costs $1600, what is its per-carat price?

a) $200
b) $400
c) $800
d) $1600

Correct Answer: b) $400

6. What is the cost of a 0.25-carat ruby that sells for $400 per carat?

a) $25
b) $50
c) $100
d) $400

Correct Answer: c) $100

7. A 1-carat round emerald would typically cost less than a 1-carat emerald-cut emerald, all other factors being equal.

a) True
b) False

Correct Answer: a) False

8. All step cuts are emerald cuts.

a) True
b) False

Correct Answer: b) False

9. Which cut is most commonly used for rubies and sapphires?

a) Emerald cut
b) Mixed cut
c) Brilliant cut
d) Cabochon cut

Correct Answer: b) Mixed cut

10. The large top facet of a stone is called?

a) Pavilion
b) Crown
c) Table
d) Girdle

Correct Answer: c) Table

11. The narrow rim around the circumference of a stone is called the:

a) Pavilion
b) Crown
c) Table
d) Girdle

Correct Answer: d) Girdle

Gemology MCQs Part-5

Test Your Knowledge in Gemology Part-5

1. Fancy cut diamonds are those with shapes that are not standard round brilliant cut.

True False

2. Alluvial deposits are those in which the gems are mined from soft rocks.

True False

3. Which gemstone has a greater range of colors?

Corundum Beryl Tourmaline

4. Rubies are sometimes oiled to help mask fractures.

True False

5. Ruby can be found in different colours other than red.

True False

6. The hardness on the Moh's Scale of spinel is 8.

True False

7. Emerald and aquamarine have the same chemical composition.

True False

8. Padparadscha sapphire is also called fancy sapphire.

True False

9. Emeralds are occasionally treated with colored fillers to make them look greener.

True False

10. Pink topaz occurs in Pakistan.

True False

Gemology MCQs Part-4

Test Your Knowledge in Gemology Part-4

1. The refractive index of diamond is 2.40.

True False

2. Cleavage in gemstones results from directional weakness in atomic bonding.

True False

3. Dark field illumination is helpful in observing asterism effect in gemstones.

True False

4. A gem material that contains absolutely no transition elements will usually be colorless.

True False

5. The Chelsea filter test is especially useful for detecting chromium.

True False

6. The most highly prized of all sapphire colors is blue sapphire from Kashmir, India.

True False

7. As emeralds get lighter in color, their value decreases.

True False

8. Padparadscha sapphire is a variety of pinkish orange sapphire.

True False

9. In the GIA color grade scale, truly colorless diamonds receive a grade of “D.”

True False

10. Lasering as an enhancement process is used to improve the appearance of diamonds.

True False

Gemology MCQs Part-3

Gemology Multiple-Choice Questions

21. Separating natural pink sapphire from synthetic pink sapphire commonly relies upon a microscopic study.

True False

22. In a round brilliant cut, the total number of facets is:

57 59 60 None of the above

23. A spectroscope is used to detect the spectrum.

True False

24. Refraction is the bending of light.

True False

25. Five carats are equal to one gram.

True False

26. If a ruby weighs 150 carats, how many grams would it weigh?

30 grams 20 grams 10 grams None of the above

27. The coloring agent in blue sapphire is Titanium and Iron.

True False

28. To display the cat’s eye phenomenon, gems should be cut in a round brilliant shape.

True False

29. Step-cut gemstones can be distinguished from brilliant-cut gemstones by the shape of their facets.

True False

30. Which of the following is not found in the anisotropic system?

Emerald Ruby Spinel

Gemology MCQ Part 2

Gemology MCQs Part 2

 

Test Your Knowledge in Gemology

1. Pink variety of beryl is called morganite.

a) True b) False

2. The flashes of color that are characteristic of a diamond's brilliance are caused by

a) birefringence b) anisotropism c) dispersion

3. The color of indicolite and Rubylite are usually

a) Pink & blue b) Green & pink c) Blue & pink

4. A one-carat round emerald appears larger than a one-carat round sapphire.

a) True b) False

5. The specific gravity of Topaz is more than Quartz.

a) True b) False

6. A refractometer can be used to measure refractive indices of any polished gem or mineral.

a) True b) False

7. Horse tail inclusion occurs in Demantoid garnet.

a) True b) False

8. Curved growth bands are characteristic of Synthetic ruby.

a) True b) False

9. 1(one) carat is equal to 100 cents or points.

a) True b) False

10. Thermal detector can be used to measure specific gravity.

a) True b) False

Gemology MCQs Part-1

Gemmology Theory Quiz

1. Citrine is

a) Yellow Quartz b) Purple Quartz c) None of the above

2. Amethyst is

a) Purple Quartz b) Yellow Quartz c) None of the above

3. Topaz has a refractive index that is

a) High with respect to Quartz b) Low with respect to Quartz c) About the same as Quartz

4. Chalcedony varieties include

a) Agate b) Ruby c) Onyx d) a & c

5. Synthetic citrine is difficult to distinguish from natural citrine

a) True b) False

6. Sapphire and Ruby are names given to

a) Blue and Red varieties of Corundum b) Blue and Red varieties of Beryl c) None of the above

7. The colorless variety of beryl is called Goshenite

a) True b) False

8. Clarity in Emeralds

a) Is commonly improved by Oiling filling b) Is not important c) None of the above

9. The most historically important source of emerald is Colombia

a) True b) False

10. The color of ruby is usually red.

a) True b) False

 

Emeralds from Ethiopia

Ethiopia, known for being the oldest independent country in Africa and one of the oldest in the world. Its breathtaking landscapes, range from mountains over 4500m high to salt plains 150m below sea level (Springer). The beauty of Ethiopia extends to its minerals with opals being one of their most famous gems. Now, with the discovery of emeralds, Ethiopia is now providing an ethical source of emeralds to the gem trade.

Emerald Mining Districts

The major emerald mining districts in Ethiopia are the Shakiso district in the Oromia region, and the Kenticha and Borena mines. Ethiopian emeralds display a diverse range of colours, including deep green, bluish-green, and sometimes yellowish-green shades. This colour range is determined by the presence and concentration of chromium and vanadium, which gives the gemstone its distinctive green hue. Ethiopian emeralds typically exhibit high levels of transparency and clarity, which enhances their visual appeal.

Growing Demand

Emeralds from Ethiopia have experienced a steady increase in demand since their discovery, as their unique characteristics have attracted attention from gemstone enthusiasts and collectors worldwide. While Ethiopian emeralds have not yet achieved the same level of recognition as their Colombian or Zambian counterparts at high-profile auctions, they have been gradually gaining ground.

Sustainable Mining

The Ethiopian government has implemented mining laws and regulations to ensure that mining companies comply with environmental protection guidelines, minimize the ecological impact, and promote sustainability (Empyrean Gems).

Mimetolith Topographic on chert

This Mysterious Stone Reveals the Face of an Old Lady – Naturally Formed or Nature’s Art?

Discover a rare mimetolith – a naturally occurring stone that eerily resembles the face of an old lady. Nature’s sculpture or just coincidence? You decide

Have you ever seen a stone so realistic, it seems like Mother Nature carved it herself? You're about to witness one of the most intriguing mimetoliths ever discovered – a naturally formed chert stone with the astonishing topographic appearance of an old lady's face. This isn’t a sculpture or a manmade carving – it’s 100% natural.

What is a Mimetolith?

A mimetolith is a naturally occurring rock, mineral specimen, or loose stone that resembles the shape or pattern of something recognizable, like a human face, animal, tree, or even a plant. These fascinating forms are created by millions of years of geological activity, erosion, and mineral deposit patterns.

The Viral Stone: A Chert with a Story to Tell
The stone in the image is a piece of chert, a hard and fine-grained sedimentary rock known for its durability and unique visual features. What makes this specimen truly extraordinary is the clearly visible formation that mirrors the profile of an elderly woman, complete with what appears to be facial contours, eyes, a nose, and even a suggestion of wrinkled skin.

Why This Mimetolith Is Going Viral

• The resemblance is shockingly lifelike

• It’s a one-in-a-million geological formation

• Viewers are calling it “Nature’s Mona Lisa”

• It's sparking debate: natural coincidence or divine artistry?

Perfect for Rock Collectors and Mystery Lovers
Whether you’re a passionate geology enthusiast, a lover of natural wonders, or someone fascinated by pareidolia (the human tendency to see faces in objects), this mimetolith is bound to capture your imagination.

Watch this video for more information 

Mimetolith Topographic on chert

Mimetolith Topographic on chert

Mimetolith Topographic on chert

Mimetolith Topographic on chert

Mimetolith Topographic on chert

All about "Yooperlite".

 "Yooperlite" is a trade name used to refer to fluorescent pebbles found along the beaches of Lake Superior in Michigan. These unique rocks are a type of syenite containing the mineral sodalite, which exhibits a distinct fluorescence when exposed to ultraviolet (UV) light. 

Yooperlite video

The term "Yooperlite" pays homage to the residents of Michigan's Upper Peninsula, who are colloquially known as "Yoopers." Using a UV fluorescent light to illuminate these rocks reveals their captivating glow, making them a popular find among rockhounds and collectors.

Scheelite Details

 

Scheelite Information

Scheelite is a calcium tungstate mineral with the chemical formula CaWO4. It is an important ore of tungsten, used in the production of tungsten alloys and for making filaments for electric lamps.

Physical Properties of Scheelite

• Color: brownish yellow, orange, greenish yellow, yellow, brown, black, colorless
• Crystal System: Tetragonal
• Hardness: 4.5 - 5.0
• Cleavage: {110} Indistinct, {001} Indistinct
• Luster: Vitreous (Glassy)
• Streak: White
• Transparency: Transparent, Translucent
• Specific Gravity: 5.9 - 6.1 (Heavy)
• Diaphaneity: Transparent to translucent

Optical Properties of Scheelite

• Refractive Index: 1.920 - 2.010
• Birefringence: 0.080 - 0.090
• Pleochroism: Weak

Scheelite From China 

Occurrences of Scheelite

Scheelite is found in hydrothermal veins, granitic rocks, and in skarns. It is also found in contact metamorphic deposits and in high-temperature greisen deposits. It is commonly associated with minerals such as calcite, fluorite, apatite, wolframite, molybdenite, and topaz.

Similar Topics 

Triplite👆

Epidote☝

Allanite☝

Piemontite☝

Zoisite☝

Clinozoisite☝

Tawmawite☝

 

Premier Rose Diamond

Overview

One of the most significant diamonds found in the Premier mine (now the Cullinan mine) in South Africa was the 353.9 carat (ct) Premier Rose rough. 

The diamond crystal was found in 1978 and named after Rose Mouw who helped plan and mark it for cutting.

 She and her husband Joe Mouw, owners of Mouw Diamond Cutting Works, purchased the rough diamond and partnered with William Goldberg to cut it into three gems – the Premier Rose (D-Flawless pear diamond weighing 137.02 ct), Little Rose (31.48 ct D-Flawless pear diamond), and Baby Rose (2.11 ct D-Flawless round brilliant diamond). The Premier Rose took six months to plan and cut.

Specifications

• Weight: 137.02 carats
• Cut: Pear
• Color: D-Flawless
  
  Related Topics:
  What Is A Triple X Diamond? The Secret Behind Investing In These Rare Diamonds☝
  
  Detecting Treated, Synthetic, Colour- Enhanced and CVD Diamond☝
  USA States Gemstones☝

Synthetic Flame Fusion Ruby in Mother Rock and its Identification Tips (Ruby Scam: Be alert)

A man brought a lot of the ruby from Afghanistan for certification.

Synthetic ruby in the mother rock 

Most of the host rock (mother rock or parent rock) of nature, ruby, is marble or calcite. Marble and calcite are abundant and easily available. So the scammer takes a piece of marble and cleverly embeds the synthetic flame fusion ruby in it. 

Identifying Synthetic Ruby Embedded in Marble/Calcite Host Rock

If you suspect that a ruby embedded in marble or calcite may be synthetic, there are a few things to look out for to help you identify it.

1. Pits and Bubbles

One of the most common signs that a ruby embedded in marble or calcite is synthetic is the presence of pits and bubbles. These can often be seen with the naked eye and are evidence that the ruby was embedded in the host rock using a clever technique.

Pits/bubbles seen 

Pits/bubbles seen 

Pits/bubbles seen 

2. Curved Striations and Bubbles in Ruby

Synthetic ruby in the mother rock

Another thing to look out for are curved striations and bubbles within the ruby itself. These can be difficult to see, but if you look at the ruby under a magnifying glass or microscope, you may be able to spot them. These are also evidence that the ruby is synthetic.

If you suspect that a ruby embedded in marble or calcite is synthetic, it's always a good idea to have it examined by an expert gemologist to confirm your suspicions.

                           

  

Internal Inclusions in Flame Fusion / Verneuil Ruby

Flame fusion, also known as the Verneuil process, is a popular method used to produce synthetic rubies. This process involves heating fine alumina powder and melting it to form a boule, which is then cut into gemstones. While synthetic rubies produced through this method can be of high quality, they often contain internal inclusions that can be used to distinguish them from natural rubies.

Internal Inclusions

One of the most common internal inclusions in flame fusion rubies is gas bubbles. These bubbles can be round or elongated in shape and are often visible under magnification. Additionally, flame fusion rubies may contain curved growth lines, wispy veils, and color banding, which can also be seen under magnification.

Identification Tips

If you suspect that a ruby may be flame fusion synthetic, look for the following clues:

• Gas bubbles
• Curved growth lines
• Wispy veils
• Color banding
• Low levels of chromium and iron

It's important to note that not all flame fusion rubies will exhibit these characteristics, and some natural rubies may also contain gas bubbles and other inclusions. If you are unsure about the authenticity of a ruby, it's always best to have it examined by a professional gemologist.

Flame Fusion / Verneuil Ruby

The flame fusion, or Verneuil process, is a popular method used to produce synthetic rubies. This process involves heating fine alumina powder and melting it to form a boule, which is then cut into gemstones. While synthetic rubies produced through this method can be of high quality, they often contain internal inclusions that can be used to distinguish them from natural rubies.

The Verneuil process can also be used to produce other synthetic gems, such as spinel, rutile, and strontium titanate.

Air Bubbles in synthetic ruby

Small bubbles in synthetic ruby

Curve line in synthetic ruby

Small bubbles in synthetic ruby

Curve lines with  air bubbles in Synthetic Ruby