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The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 1 as the hardness of talc, the softest mineral. When scraped on a streak plate , talc produces a white streak, though this indicator is of little importance, because most silicate minerals produce a white streak.
Amethyst crystals – a purple quartz Apophyllite crystals sitting right beside a cluster of peachy bowtie stilbite Aquamarine variety of beryl with tourmaline on orthoclase Arsenopyrite from Hidalgo del Parral, Chihuahua, Mexico Aurichalcite needles spraying out within a protected pocket lined by bladed calcite crystals Austinite from the Ojuela Mine, Mapimí, Durango, Mexico Ametrine ...
Gold fillings have excellent durability, wear well, and do not cause excessive wear to the opposing teeth, but they do conduct heat and cold, which can be irritating. There are two categories: cast gold fillings (gold inlays and onlays) made with 14 or 18 kt gold, and gold foil made with pure 24 kt gold that is burnished layer by layer.
The normal color of enamel varies from light yellow to grayish (bluish) white. It has been suggested that the color is determined by differences in the translucency of enamel, yellowish teeth having a thin, translucent enamel through which the yellow color of the dentin is visible and grayish teeth having a more opaque enamel.
P11-4 is a self-assembling β-peptide. It builds a 3-D bio-matrix with binding sites for Calcium-ions serving as nucleation point for hydroxyapatite (tooth mineral) formation. The high affinity to tooth mineral is based on matching distances of Ca-ion binding sites on P11-4 and Ca spacing in the crystal lattice of hydroxyapatite.
The affected areas of the tooth change color and become soft to the touch. Once the decay passes through the enamel, the dentinal tubules , which have passages to the nerve of the tooth, become exposed, resulting in pain that can be transient, temporarily worsening with exposure to heat, cold, or sweet foods and drinks. [ 15 ]
Enamel is the hardest substance in the human body and contains the highest percentage of minerals, [3] 96%, with water and organic material composing the rest. [4] The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. [5] Enamel is formed on the tooth while the tooth is developing within the gum, before it erupts into ...
Struvite (magnesium ammonium phosphate) is a phosphate mineral with formula: NH 4 MgPO 4 ·6H 2 O. Struvite crystallizes in the orthorhombic system as white to yellowish or brownish-white pyramidal crystals or in platy mica-like forms. It is a soft mineral with Mohs hardness of 1.5 to 2 and has a low specific gravity of 1.7. It is sparingly ...