Jasi

Jasi (ing.gypsum) ni madini yanayoptikana mahali pengi ambayo kikemia ni sulfati ya kalsi . Fomula yake ni CaSO₄·2H₂O. Ni madini laini sana yakiwa na ugumu wa 2 kwenye skeli ya Mohs. Inaweza kukwaruzwa kwa kucha.

Jasi

Kiasili inapatikana mara nyingi kama fuwele; jasi safi haina rangi lakini ikichanganywa na madini mengine kuna fuwele za rangi kadhaa. Kwa matumizi ya kibinadamu huchomwa ikipatikana baadaye kama unga nyeupe. Unga wa jasi unaweza kuchanganywa na maji ukipokea umbo lolote baada ya kukauka tena.

Jasi imetumiwa tangu kale katika ujenzi, hasa kwenye lipu. Katika ujenzi wa kisasa bao za jasi na matofali ya jasi hutumiwa kujenga kuta za ndani zisizobeba mzigo. Kuta hizi za jasi huzuia au kuchelewesha moto ndani ya nyumba^[1]. Hutumiwa pia kama dawa la kilimo na chalki ya ubao shuleni. Wasanii hutumia jasi kwa sanamu.

Picha

• Maumbo tofauti ya jasi asilia
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  Fuwele za jasi kutoka Australia - rangi inatokana na ioni za shaba.
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  Unusual selenite gypsum from the Red River, Winnipeg, Manitoba, Canada
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  Classic "ram's horn" gypsum from Santa Eulalia, Chihuahua, Mexico, 7.5×4.3×3.8 cm
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  Desert rose, 47 cm long
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  Gypsum from Pernatty Lagoon, Mt Gunson, Stuart Shelf area, Andamooka Ranges - Lake Torrens area, South Australia, Australia
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  Gypsum with crystalline native copper inside
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  Gypsum from Swan Hill, Victoria, Australia. The colouring is due to the copper oxide
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  Waterclear twined crystal of the form known as "Roman sword". Fuentes de Ebro, Zaragoza (Spain)
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  Bright, cherry-red gypsum crystals 2.5 cm in height colored by rich inclusions of the rare mineral botryogen
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  Gypsum from Naica, Mun. de Saucillo, Chihuahua, Mexico
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  Golden color gem, "fishtail"-twinned crystals of gypsum sitting atop a "ball" of gypsum which is composed of several single bladed crystals