The value of a gemstone is determined by several factors, commonly known as the "Four Cs": Color, Clarity, Cut, and Carat weight. Additionally, rarity, durability, and market demand play significant roles in determining a gemstone's value. Each gemstone type may have specific qualities that are particularly prized, such as the "pigeon blood" red of rubies or the velvety blue of fine sapphires.

Distinguishing between natural and synthetic gemstones often requires expert knowledge and specialized equipment. However, some general indicators include:

• Inclusions: Natural stones often have inclusions, while synthetics may be flawless or have characteristic inclusions from the manufacturing process.
• Price: If the price seems too good to be true for a supposedly high-quality natural stone, it might be synthetic.
• Color: Some synthetic stones may have colors that are too perfect or intense to occur naturally.

For a definitive answer, it's best to consult a certified gemologist or have the stone tested in a reputable gemological laboratory.

Proper care for gemstones varies depending on the type of stone, but here are some general guidelines:

• Clean your gemstones regularly with a soft brush and mild soap in warm water.
• Avoid using harsh chemicals or ultrasonic cleaners, especially for softer or more porous stones.
• Store gemstones separately to prevent scratching.
• Remove gemstone jewelry before engaging in activities that might subject them to impact or harsh chemicals.
• Have your gemstone jewelry checked and professionally cleaned periodically.

Always research the specific care requirements for your particular gemstone, as some may need special attention.