TOPAZ. 49 The dark wine-yellow passes from orange-yellow through cherry-red into violet-blue *. It occurs seldom massive; disseminated, and in rolled pieces ; most frequently crystallised. Its crystallizations are as follow: 1. Oblique four-sided prism, rather acutely acuminated by four planes, which are set on the lateral planes •)-. 2. N° 1. in which the acuter lateral, edges are bevel led ; or it may be viewed as an eight-sided prism, in which two and two lateral planes meet under obtuse angles. Fig. 30. 3. N 1, & 2., with a double acumination ; the planes of the second acumination set on those ot the first. 4. N° 2. with a triple acumination; in which the planes of the one always rest on those of the others. 5. N" 2. in which the angles on the acute edges, and the summits of the acuminations, are truncated. Fig. 31. 6- N° 4. in which the angles on the acute and obtuse edges are truncated. Fig. 32. N 1, & 2 , in which the summits of the acumina tions are truncated. 8. The The violct-blue variety is very rare: in proof of this, it may be men- tea^T th ' lt Mr V ° n der NU11 ° f Vie " nn ’ the proprietor of one of the most descr'te' <lnd ‘ natrUCtive cabinets in Europe, and which has teen excellently ‘ d by Mohs, paid 1500 ducats for a single specimen of violet-blue coloured to pa *. VId . Von ^ KphcmcrMun According to Haiiy, the primitive form of topaz is a rectangular octa- Voi. I. 1)
