Search results
Results from the WOW.Com Content Network
Today this tourmaline locality (type locality for dravite) at Dobrova (near Dravograd), is a part of the Republic of Slovenia. [9] Tschermak gave this tourmaline the name dravite, for the Drava river area, which is the district along the Drava River (in German: Drau, in Latin: Drave) in Austria and Slovenia.
Some solid substances that are not minerals have been assigned a hardness on the Mohs scale. Hardness may be difficult to determine, or may be misleading or meaningless, if a material is a mixture of two or more substances; for example, some sources have assigned a Mohs hardness of 6 or 7 to granite but it is a rock made of several minerals ...
Elbaite, a sodium, lithium, aluminium boro-silicate, with the chemical composition Na(Li 1.5 Al 1.5)Al 6 Si 6 O 18 (BO 3) 3 (OH) 4, [4] is a mineral species belonging to the six-member ring cyclosilicate tourmaline group. Elbaite forms three series, with dravite, with fluor-liddicoatite, and with schorl.
Mohs hardness of materials (data page) Vickers hardness test; Brinell scale This page was last edited on 16 November 2024, at 12:16 (UTC). Text is available ...
Mohs scale hardness: 7.5–8.0: Luster: Vitreous to resinous: ... biotite, and tourmaline. Beryl is sometimes found in metasomatic contacts of igneous intrusions with ...
It crystallizes in the orthorhombic – dipyramidal crystal system as brown, green, yellow to colorless slender tourmaline like prisms or in massive fibrous forms. It has a Mohs hardness of 7 and a specific gravity of 3.3 to 3.34. Its indices of refraction are nα=1.660 – 1.671, nβ=1.673 – 1.683 and nγ=1.674 – 1.684.
Other manufacturers market silicon carbide gemstones under trademarked names such as Amora. On the Mohs scale of mineral hardness (with diamond as the upper extreme, 10) moissanite is rated as 9.5. [4] As a diamond alternative, Moissanite has some optical properties exceeding those of diamond.
The Mohs hardness scale [25] is a commonly used tool in lapidary to help measure a mineral's scratch hardness. A mineral's scratch hardness is measured by seeing how easily scratched it is, and what other minerals on the Mohs hardness scale can scratch it.