Prehnite is a calcium aluminum silicate mineral with a hardness of 6 to 6.5. Its crystal system is orthorhombic. It usually occurs in massive, botryoidal, granular or stalactitic habits, but can also (rarely) form prismatic, pyramidal or tabular crystals. The color is usually yellow-green, but it can be yellow, white, gray or colorless. Prehnite links the heart with the will, so one’s power is used to carry out the promptings of the heart. When the will is linked to the heart rather than the egoic mind, one’s actions take on the colorations of peace and one’s desires are in alignment with the highest good possible in each situation. Prehnite quiets restlessness, nervousness and worry. It helps one stay in the present moment and avoid the unhealthy use of the imagination (e.g., visualizing all the disastrous possible futures!). Prehnite reminds one of the existence of one’s personal power at the same time it invokes the use of that power in the service of love. Prehnite is a good stone to take on retreats or to other situations in which one must undergo some sort of spiritual discipline. These stones will assist one in quieting dissonance within the mind and ‘setting one’s heart’ on the goal of spiritual surrender. Prehnite is a purifier for the energies of the digestive system, as well as the kidneys, adrenals, liver and gallbladder. It emanates a vibration harmonious with smooth and integrated functioning of these areas of the physical body.
Simmons, Robert; Ahsian, Naisha. The Book of Stones, Revised Edition: Who They Are and What They Teach (several pages). North Atlantic Books. Kindle Edition.