According to Vaidik authority, natural gemstones radiate "astral" powers! Fine, flawless gems promote good fortune, while poor quality gems have the opposite affect
(Garud Puraan: Chapter 68, Verse 17)

"A gem free from all impurities and radiating its characteristic internal luster should be looked upon as an 'escort' of good luck. A gem which is cracked, fissured, devoid of luster, or appearing rough or sandy, should not be used at all."
(Agni Puraan: Chapter 246, Verse 7 & 8 (Circa 2000 BC)

Rock Crystal: Vaidik Text
The potent semen of Bal transformed into the seeds of quartz (rock crystal), also known as Bheeshm stones. These seeds germinated primarily in the Himaalaya and the lands to their north. These crystals are usually transparent and colorless, and are often so brilliant that they are mistaken for diamonds. Any one respectfully wearing a pure quartz crystal set in gold will attain good fortune in this life and be protected from dangerous animals such as tigers, leopards, wolves, elephants, and lions. Pure quartz is also an amulet giving the wearer extraordinary sexual prowess. Wearing quartz while offering libations to departed ancestors insures them lasting happiness. It is also a talisman against drowning, burning and theft. These attributes pertain to pure flawless quartz, and knowledgeable gemologists advise that flawed varieties that are fractured, or discolored should be completely avoided.
(Garud Puraan, Chapter 69)

Puraan Against Flawed Ratn
Natural Ruby : Shree Soot Jee said, "A ruby, although genuine, should not be worn if it has strong color banding, excessive inclusions within like numerous internal cracks, a sandy appearance, a rough surface, or is dull and lusterless. Anyone using such a flawed ruby, even out of ignorance, will suffer from disease, or loss of fortune.”
[Garud Puraan, Chap 70]

Natural Pearl : Shree Soot Jee said, "A pearl of the auspicious quality should be white, translucent, round in shape, lustrous, and of good weight and size."
[Garud Puraan, Chap 69]

Natural Yellow Sapphire : Shree Soot Jee said, "Yellow sapphires must be evenly colored, flawless and well shaped in order to be considered auspicious.
[Garud Puraan, Chap 74]

Natural Hessonite (Karketan) : Shree Soot Jee said, "Hessonites which are flawed, lack luster, or white or bluish in color are considered inferior and inauspicious."
[Garud Puraan, Chap 75]

Natural Emerald : Shree Soot Jee said, "Emeralds considered inauspicious are blackish, devoid of luster, appearing dirty inside or dried and brittle. Anyone concerned with their own well-being should never purchase or wear any oiled, dyed, or treated emerald. Also, emeralds of mixed colors are strictly forbidden."
[Garud Puraan, Chap 71]

Natural Diamond : Shree Soot Jee said, "Anyone wearing a seriously flowed or clouded diamond which refracts a reddish glimmer from defective facet edges, will surely be abandoned by the goddess of fortune. A diamond containing red spots will bring ruin."
[Garud Puraan, Chap 68/2]

Natural Blue Sapphire : Shree Soot Jee said, "Blue sapphires and all other gems should never be subjected to burning for improving their color and clarity, as misfortune will certainly befall anyone doing so."
[Garud Puraan, Chap 72]

Natural Red Coral : Shree Soot Jee said, "A well polished, bright coral with rich, soothing dark-red colors and without flaws is considered very auspicious. It possesses power to increase the riches and wheat supplies of its wearer and also removes obstacles and dangers."
[Garud Puraan, Chap 80]

Natural Red Garnet : Shree Soot Jee said, "As with rubies, garnets colored like the petals of the red lotus are considered the rarest and most beautiful and possess the mystic virtue of increasing both the wealth and progeny of their owners."
[Garud Puraan, Chap 77]

Natural Green Jade : Shree Soot Jee said, “Among all gems, fine quality jade has the greatest ability to remove negative Kaarmic reactions."
[Garud Puraan, Chap 79]