Natural Aquamarine Chunks sizes vary due to natural nature. 

Aquamarine is a pale-blue to light-green variety of beryl. The colour of aquamarine can be changed by heat. The aquamarine has a chemical composition of Be₃Al₂Si₆O₁₈, also containing Fe²⁺. It has a hardness of 7.5 to 8. Aquamarine contains no or few noticeable inclusions.

Aquamarine a crystal that represents courage and is said to calm a busy mind. May harmonise its surroundings and bring peace. I have read that Sailors used it as a talisman to against drowning.