A gemstone or gem (also called a fine gem, jewel, or precious or semi-precious stone) is a piece of mineral crystal, which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli) or organic materials that are not minerals (such as amber or jet), are also used for jewelry and are therefore often considered to be gemstones as well.

Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity is another characteristic that lends value to a gemstone. Apart from jewelry, from earliest antiquity engraved gems and Hardstone carvings, such as cups, were major luxury art forms. A gemstone maker is called a lapidary or gem cutter; a diamond worker is a diamantaire.

Gemstones are so fascinating! Their colors, properties, myths, and legends are diverse and fascinating. Folklore about stones has been revered and honored for centuries in all cultures.

What are minerals or gems? These tips of question usually come around in our mind whenever we discuss gems. So do you have any idea that there are more than 4000 minerals naturally occurring on earth and have some kind of chemical composition and specific crystal structure? These minerals are known as gems or jewels in gemology.

What are minerals or gems?

These types of question usually come around in our mind whenever we discuss gems. So do you have any idea that there are more than 4000 minerals naturally occurring on earth and have some kind of chemical composition and specific crystal structure? These minerals are known as gems or jewels in gemology.

1. Yellow Sapphires:

yellow sapphire gemology

 

Yellow sapphire is a variety of corundum that consisting of aluminum oxide too. The chemical formula for sapphire stone is Aluminium oxide, Al2O3 and its hardness is measure in moh’s scale which is 9 mohs most harder stone after diamond. Some interesting things that make yellow sapphire precious one is Specific gravity, Refractive index, and Luster.

Specific gravity: 4.0~4.1

Refractive index: nω=1.768–1.772, nε=1.760–1.763,

Luster: Vitreous

2. Blue sapphire:

Blue sapphire gemologyBlue sapphire also belongs to corundum family with a chemical formula of yellow sapphire i.e. Aluminium oxide, Al2O3. As it also belongs to corundum family its all chemical properties are the same as Yellow sapphire.

3. Ruby:

Ruby GemologyRuby is a precious stone in pink to blood-red colored and its chemical formula: aluminum oxide with chromium, Al2O3: Cr. Ruby is known as other variety from mineral corundum (aluminum oxide).

Physical proprieties of ruby: Specific gravity: 3.97 – 4.05

Refractive index: nω=1.768–1.772, nε=1.760–1.763,

Luster: Subadamantine, vitreous, pearly

Hardness: 9 Moh’s

4. Emerald:

Emerald GemologyEmerald is another precious green color stone from mineral beryl and its formula is Be3Al2(SiO3)6. If you talk about the physical properties of emerald that are

Specific gravity: Average 2.76

Refractive index: nω = 1.564–1.595, nε = 1.568–1.602

Luster: Vitreous

Hardness: 7.5-8 Moh’s

5. Pearl:

Pearl GemologyPearl is an organic mineral that a living shelled mollusk. Pearl stone is found in Variety of colors like black, pink, white, golden, etc.

Physical properties of pearl are:

Specific gravity: 2.60–2.85

Refractive index: Common pearl: 1.52-1.66, Black pearl: 1.53-1.69

Formula: Calcium carbonate, CaCO3

Hardness: 2.5–4.5 Moh’s

6. Coral:

Coral GemologyCoral is an organic stone or hard skeleton of red coral branches. It usually found under the deep sea. Physical properties of coral

Specific gravity: 2.6–2.7

Hardness: 4 Moh’s