Taaffeite is one of the world's rarest gemstones, prized for its exceptional rarity and brilliance. Found in shades of lavender, violet, pink and colorless, it is significantly rarer than diamonds. Often mistaken for spinel due to its similar appearance and colors. Taaffeite has a hardness of 8–8.5 on the Mohs scale.

Serendibite is an exceptionally rare gemstone first discovered in Sri Lanka. Known for its deep blue, green, and blackish hues. It is highly prized by collectors due to its rarity. With a hardness of 6.5–7 on the Mohs scale, serendibite is a remarkable and sought-after collector's gem.

Sinhalite is a rare gemstone first discovered in Sri Lanka and often mistaken for peridot or brown sapphire. It occurs in yellow, honey, brown and greenish-yellow shades. With a hardness of 6.5–7 on the Mohs scale, sinhalite is valued by collectors for its rarity and attractive colors.

Kornerupine is a rare gemstone known for its pleochroic colors, displaying shades of green, brown, yellow, and bluish-green from different angles. Found in Sri Lanka and a few other locations, it has a hardness of 6.5–7 on the Mohs scale and is prized by collectors and gem enthusiasts.