Prehnite is an inosilicate of calcium and aluminium. Prehnite crystallises in the orthorhombic crystal system, and most often forms as stalactitic or botryoidal aggregates, with only just the crests of small crystals showing any faces, which are almost always curved or composite. Very rarely will it form distinct, well-individualised crystals showing a square-like cross-section, including those found at the Jeffrey Mine in Asbestos, Quebec, Canada. Prehnite is brittle with an uneven fracture and a vitreous to pearly luster. Its hardness is 6-6.5, its specific gravity is 2.80-2.90 and its colour varies from light green to yellow, but also colourless, blue, pink or white. In April 2000, rare orange prehnite was discovered in the Kalahari Manganese Fields, South Africa. Prehnite is mostly translucent, and rarely transparent.
Though no longer a zeolite, prehnite is discovered related to minerals such as datolite, calcite, apophyllite, stilbite, laumontite, heulandite and so forth. In veins and cavities of basaltic rocks, now and again in granites, syenites, or gneisses. It is a trademark mineral of the prehnite-pumpellyite metamorphic facies.
Prehnite is a translucent to transparent gem-quality hydrated calcium aluminum silicate. It was the first mineral to be named after an individual, and it was also the first mineral to be described from South Africa, long before South Africa became one of the most important sources for precious and semi-precious gems. It was first described in 1788 after it was discovered in the Karoo dolerites of Cradock, South Africa. Prehnite was later named after its discoverer, Colonel Hendrik von Prehn (1733-1785), a Dutch mineralogist and an early governor of the Cape of Good Hope colony.
Until recently, prehnite become a unprecedented collector's gemstone, however new deposits have now made it extra simply available. In China, prehnite is sometimes known as 'grape jade' thanks to its traditional nodule formations which often resemble a group of grapes. Its color is mostly a gentle apple-inexperienced, which is pretty precise to prehnite, however it could additionally occur in rarer shades along with yellow, orange and blue.
Prehnite is typically semi-transparent to translucent with a chemical formula of Ca2Al(AlSi3O10)(OH)2. Its color is usually yellow-green to apple-green. Prehnite is considerably hard with a rating of 6 to 6.5 on the Mohs scale. It has a specific gravity ranging from 2.82 to 2.94 and a refractive index of 1.611 to 1.669. Prehnite is in the orthorhombic crystal class, usually found in radiating botryoidal (grape-like) aggregate forms, and rarely as tabular and pyramidal crystals. When heated, prehnite crystals can sometimes give off water. It has a brittle tenacity and an uneven fracture. When polished, prehnite has a vitreous to pearly luster. Prehnite may be confused with apatite, jade or serpentine.
Prehnite happens within the veins and cavities of mafic volcanic rock. It is a standard fabricated from low-grade metamorphism. Primary deposits of prehnite are sourced from several locations around the arena. Some of the maximum essential deposits come from Africa (Namibia, South Africa), Australia (Western Australia, Northern Territory), Canada, China, Germany, Scotland, France and the United States (New Jersey, Pennsylvania and Virginia).
Rare, orange colored prehnite has been observed in South Africa. Quebec, Canada is thought to produce prehnite with distinct, man or woman crystals.
There are no closely related gemstones, but there are several gemstones which can have a very similar appearance (colour and luster), including jade, apatite, serpentine, brazilianite, periclase, chrysoprase , peridot , smithsonite and hemimorphite. Prehnite is also often found and associated with many microporous, aluminosilicate zeolite minerals such as datolite, calcite, apophyllite, stilbite and heulandite.
Prehnite is considered a stone of unconditional love and the crystal to heal the healer. It complements precognition and internal knowing. Enables you always to be prepared. Prehnite calms the surroundings and brings peace and protection. It teaches the way to be in concord with nature and the fundamental forces. Helpful for ?Decluttering? Letting go of possessions you not need, assisting those who hoard possessions, or love, due to an inner lack. Prehnite alleviates nightmares, phobias and deep fears, uncovering and restoration the dis-ease that creates them. It is a stone for dreaming and remembering. Beneficial for hyperactive kids and the causes that underlie the situation.
Prehnite heals the kidneys and bladder, thymus gland, shoulders, chest and lungs. It treats gout and blood problems. Prehnite repairs the connective tissue within the body and may stabilise malignancy.
| Chemical Formula | Ca2Al2Si3O12(OH) |
| Colour | Green |
| Hardness | 6 - 6.5 |
| Crystal System | Orthorhombic |
| Refractive Index | 1.61 - 1.64 |
| SG | 2.8 - 3.0 |
| Transparency | Translucent |
| Double Refraction | .030 |
| Luster | Vitreous, waxy |
| Cleavage | 1,1;3,1 |
| Mineral Class | Prehnite |
