What is the most beautiful gemstone ?

Which gemstone is regarded as the most beautiful?  

Note: Beauty is subjective; gemstone choice may be based on color, rarity, or personal preference.

Gemstone popularity and origin:  
Opal: Mined mostly in Australia; shows opalescence.  
Amethyst: Shades of purple; found in Brazil, Uruguay, North Carolina (USA).  
Emerald: Green, birthstone for May; symbolizes love and prosperity.  
Ruby: Red/pink tones; birthstone for July.  
Larimar: Rare azure stone from Caribbean, healing properties.  
Moonstone: Rainbow sheen, birthstone for June, optical adularescence.  

Note: Informational purposes only; individual perception of beauty may vary.  

Gemstone beauty:  
There is no single "best" gemstone; all have importance. Emerald is considered appealing for color, cut, and historical/astrological significance.  

Note: Personal opinion; informational only.