The crescent symbol is primarily used to represent the Moon, not necessarily in a particular lunar phase. When used to represent a waxing or waning lunar phase, "crescent" or "increscent" refers to the waxing first quarter, while the symbol representing the waning final quarter is called "decrescent".
The Luna, half moon, or sickle of the moon, waning and waxing moon, is a sign of fertility and to the cycles of life and death. It represents the changing of the seasons and the ebb & flow of the tide.
Rainbow moonstone is thought to bring balance, harmony and hope while enhancing creativity, compassion, endurance and inner confidence. It is also very helpful to strengthen intuition and psychic perception, especially offering us visions of things that we are not immediately aware of.
*Measures approximately 1 inch