GEMSTONE SPECIES - INORGANIC

Red spinel is a stunning, naturally occurring gemstone that has often been mistaken for ruby throughout history due to its vivid red colour. Today, it is appreciated as a precious gem in its own right, known for its brilliance, durability, and rich hues.
Why Red Spinel is Special:
--> Often, untreated, unlike many rubies.
--> Offers exceptional fire and brilliance.
--> It was historically misidentified that famous rubies like the Black Prince’s Ruby in the British Crown Jewels are red spinels!

How to differentiate from Ruby:
--> Spinel is isotropic (does not show double refraction like ruby).
--> Typically has fewer inclusions and more brilliance.
--> Modern gemology tools (like spectroscopy and RI testing) are used for accurate identification.

Blue spinel is a rare and naturally beautiful gemstone from the spinel family, admired for its rich, saturated blue hues and excellent clarity. Unlike sapphire, blue spinel is usually untreated, making it a favourite among collectors and connoisseurs.
Colours & Types: 

Cobalt Blue Spinel --> Intense blue caused by trace amounts of cobalt, most rarest and valuable.
Greyish-Blue or Steely Blue --> Caused by iron; more common, still desirable.
Violetish-Blue --> Sometimes overlaps with lavender tones.
Why Blue Spinel is Special:
Natural, untreated colour in most cases.
Brilliant sparkle and clarity due to the cubic structure.
Rare in nature, blue is among the least common spinel colours.
Historically confused with sapphire, but now prized on its own merits.
 

Colour change spinel is a fascinating variety that displays different colours under different lighting conditions, typically changing from blue, grayish, or violet in daylight to purple, reddish, or pink under incandescent light. This optical phenomenon makes it highly prized by gem collectors and enthusiasts.
Cause of Colour Change:
The phenomenon is due to trace elements (like chromium, iron, or vanadium) interacting with different light sources, similar to alexandrite.
Gem Value Factors:
Strength of colour change --> Stronger shifts are more valuable.
Clarity and cut --> Clean, well-cut stones enhance visual effect.
Size --> Larger stones showing clear colour change are rarer and more expensive. 

Star Spinel is a rare and captivating variety of spinel that exhibits a phenomenon known as asterism. This effect is typically visible as a four-rayed or six-rayed star, making it a unique and mystical gemstone.
Star Spinel vs. Star Sapphire (optical phenomenon)
Star Spinel:
Number of Rays --> Usually 4 or 6
Cause of Asterism --> Rutile or hematite inclusions
Appearance --> Often more subtle or soft-edged stars
Colour Range --> Grey, purplish, blackish, reddish
Star Sapphire:
Number of Rays --> Usually 6 (rarely 12)
Cause of Asterism --> Rutile needle inclusions
Appearance --> Sharper, more defined star pattern
Colour Range --> Blue, pink, grey, black, yellow, purple
Treatments:
Star Spinel: Often natural and untreated.
Star Sapphire: Commonly heat-treated to improve colour and asterism. 

Fancy spinel refers to spinel gemstones that come in a wide range of colours other than the classic red. These include vibrant shades of blue, pink, purple, violet, orange, grey, and even colourless. Fancy spinels are admired for their natural, untreated beauty, brilliance, and increasing rarity in fine quality.
Why Collect Fancy Spinels?
Affordability --> Generally more affordable than sapphire and ruby, despite being natural.
No Treatment --> 100% natural colour in most cases.
Rising Popularity --> Increasing demand in the high-end market and designer jewelry.

Rarity --> Some shades like cobalt-blue and neon pink are very rare and collectible.

Buying Tip
--> Look for vivid, saturated colours, good clarity, and well-cut stones.
--> Ask for gem lab certification, especially for rare blues (to verify cobalt content).