A gemstone or gem (also called a fine gem, jewel, or a 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 or organic materials that are not minerals 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 hard stone carvings, such as cups, were major luxury art forms. A gem maker is called a lapidary or gem cutter; a diamond worker is a diamantaire.
Gemstone also classified and wear according to constellation. Planet zodiac sign and lagna.
According to Master deepak ji, Whenever decide to wear planetary gems wear according to lagna chart and planet degree.
|Rashi||Lord of Rashi||Your Gem||Finger to Wear|
|1.Aries / Mesha||Mars||Red Coral||Ring finger|
|2.Taurus / Vrishbha||Ven||Diamond||Ring finger|
|3.Gemini / Mithun||Mer||Emerald||Little finger|
|4. Cancer / Karka||Moon||Pearl||Ring finger|
|5. Leo / Simha||Sun||Ruby||Ring finger|
|6. Virgo / Kanya||Mer||Emerald||Little finger|
|7. Libra /Tula||Ven||Diamond||Ring finger|
|8. Scorpio / Vrichika||Mars||Red Coral||Ring finger|
|9. Sagittarious / Dhanu||Jup||Yellow Sapphire||First finger|
|10. Capricon / Markar||Sat||Blue Sapphire||Middle finger|
|11. Aquarius / Kumbh||Sat||Blue Sapphire||Middle finger|
|12. Pisces / Meena||Jup||Yellow Sapphire||First finger|