Pukhraj
Yellow Sapphire
Planet
Jupiter (Guru)
Hardness
9.0 Mohs
KFG Gemological Archive · Since 1971
The Complete Guide to Natural Gemstones
How to evaluate origin, clarity, thermal treatment, lab certification and Ratti-to-Carat conversion before acquiring an earth-mined stone.
Est. 1971 • Mumbai Vault
Chapter 01 · The Vault Encyclopaedia
Explore Gemstones by Family
Select any gemstone to read its buying guide or browse certified pieces in our vault.
Pukhraj
Neelam
Blue Sapphire
Planet
Saturn (Shani)
Hardness
9.0 Mohs
Panna
Emerald
Planet
Mercury (Budh)
Hardness
7.5–8.0 Mohs
Manik
Natural Ruby
Planet
Sun (Surya)
Hardness
9.0 Mohs
Moonga
Red Coral
Planet
Mars (Mangal)
Hardness
3.5–4.0 Mohs
Upala
Natural Opal
Planet
Venus (Shukra)
Hardness
5.5–6.5 Mohs
Gomed
Hessonite (Gomed)
Planet
Rahu
Hardness
7.0–7.5 Mohs
Lehsuniya
Cat's Eye
Planet
Ketu
Hardness
8.5 Mohs
Keshi Moti
Keshi Pearl
Planet
Moon (Chandra)
Hardness
2.5–4.5 Mohs
Moti
South Sea Pearl
Planet
Moon (Chandra)
Hardness
2.5–4.5 Mohs
Safed Pukhraj
White Sapphire
Planet
Venus (Shukra)
Hardness
9.0 Mohs
Chapter 02 · Quality Evaluation
The 4 Pillars of Gemstone Valuation
Coloured gemstones are evaluated by natural hue saturation, provenance and clarity.
Colour & Saturation
Hue purity, tone balance and vivid saturation without dark extinction.
Clarity & Character
Eye-clean brilliance in Sapphires versus natural jardin in Emeralds.
Origin & Provenance
Ceylon, Burma, Zambia and Colombia shape rarity and optical character.
Cut & Usable Carat
Symmetrical faceting ensures maximum light return and skin contact.
Chapter 03 · Buy With Clarity
Understanding Treatments & Certification
Every natural stone at KFG carries full disclosure of its enhancement status and lab report.
100% Unheated / Untreated
Completely untouched after mining—preserving natural crystal silk and highest rarity.
Traditional Thermal / Oil
Controlled heating in Corundum or natural oil in Emerald, disclosed upfront on every SKU.
Laboratory Certification
Accompanied by verifiable lab reports (GIA, IGI, GII) stating species, weight and treatment.
Chapter 04 · Weight & Wearing Reference
Carat to Ratti Converter & Vedic Matrix
Convert astrological Ratti weight to international Metric Carats instantly.
Live Carat ↔ Ratti Calculator
1 Standard Ratti = 0.91 Carat · 1 Metric Carat = 1.095 Ratti
5.50 Ratti = 5.02 Carats. Ideal shopping range: 4.80 ct – 5.30 ct.
| Gemstone | Planet | Metal | Day |
|---|---|---|---|
| Yellow Sapphire (Pukhraj) | Jupiter | Yellow Gold | Thursday |
| Blue Sapphire (Neelam) | Saturn | Silver / Gold | Saturday |
| Emerald (Panna) | Mercury | Gold / Silver | Wednesday |
| Ruby (Manik) | Sun | Yellow Gold | Sunday |
| Red Coral (Moonga) | Mars | Gold / Copper | Tuesday |
| Pearl / Opal | Moon / Venus | Silver | Mon / Fri |
| Hessonite & Cat's Eye | Rahu / Ketu | Silver / Panchdhatu | Sat / Tue |
Chapter 05 · Personal Vault Assistance
Consult on WhatsApp
Need Personal Guidance Choosing a Stone?
Share your required Ratti/Carat weight with our Mumbai gemologists for curated recommendations.