crystal forms of the tetragonal system ,tetragonale pyramide ,pyramid rotated 45*relative to the first order. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
crystal forms of the tetragonal system ,tetragonales prisma ,four-sided rectangular column (square cross-section). - 寶石學 幅插畫檔、美工圖案、卡通及圖標
gemology, emerald is a gemstone and a variety of the mineral beryl colored green, vintage illustration - 寶石學 幅插畫檔、美工圖案、卡通及圖標
gemology, chrysoberyl is an exceptionally hard and durable gemstone vintage illustration - 寶石學 幅插畫檔、美工圖案、卡通及圖標
a standard rhombohedron, a three-dimensional figure similar to a cube but slanted. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
a hexagonal scalenohedron, a 12-faced solid common in calcite crystal formations. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
a deltoidal dodecahedron, a 12-faced solid where each face is a kite-shaped deltoid. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
a hemimorphically developed crystal of tourmaline, showing asymmetrical terminations at the top and bottom. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
an orthorhombic sphenoid, featuring four faces within the orthorhombic crystal system. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
the orthorhombic (rhombic) system ,(rhombic prism): an elongated four-sided column with a rhombic cross-section. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
a triangular dodecahedron (also known as a triakis tetrahedron), featuring 12 triangular faces. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
iron cross twin ,penetration twin formed by two pentagonal dodecahedrons. this is the famous "iron cross" characteristic of pyrite (fool's gold). - 寶石學 幅插畫檔、美工圖案、卡通及圖標
a composite crystal form showing an octahedron modified by a pentagonal dodecahedron (also known as a pyritohedron). - 寶石學 幅插畫檔、美工圖案、卡通及圖標
the orthorhombic (rhombic) system ,(brachydiagonal dome): a similar form but parallel to the shorter horizontal axis (brachy-axis). - 寶石學 幅插畫檔、美工圖案、卡通及圖標
a "flatter" rhombohedron, showing a more obtuse or compressed vertical orientation. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
the orthorhombic (rhombic) system ,(macrodiagonal dome / querprisma): a "tent-like" form consisting of two faces parallel to the longer horizontal axis (macro-axis). - 寶石學 幅插畫檔、美工圖案、卡通及圖標
crystal forms of the tetragonal system ,ditetragonale pyramide: an eight-faced pyramid where each corner of the square base is split into two. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
a dyakis dodecahedron (diploids), a 24-faced solid within the cubic crystal system. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
the orthorhombic (rhombic) system ,prisma, brachyprisma u. pyramide: a complex combination crystal showing a primary prism body, side faces of a brachy-prism, and a terminal rhombic pyramid. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
crystal forms of the tetragonal system ,tetragonale pyramide ,simple four-sided pyramid aligned with the primary axes. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
the orthorhombic (rhombic) system ,rhombic pyramid ,double pyramid (dipyramid) where the base is a rhombus rather than a square. common in sulfur crystals. - 寶石學 幅插畫檔、美工圖案、卡通及圖標
gemology, blue topaz, semi-precious gemstone renowned for its stunning icy-to-deep blue hues and excellent durability, vintage illustration - 寶石學 幅插畫檔、美工圖案、卡通及圖標
gemology, sphene, also known as titanite is a calcium titanium silicate mineral frequently found associated with feldspar in igneous and metamorphic rock, vintage illustration - 寶石學 幅插畫檔、美工圖案、卡通及圖標
gemology, amethyst is a stunning purple variety of quartz known for its distinct violet hue, vintage illustration - 寶石學 幅插畫檔、美工圖案、卡通及圖標
spinel twin ,contact twin common in the cubic system. two octahedrons are joined on a common plane. this is so characteristic of the mineral spinel that it is officially known as the "spinel law." - 寶石學 幅插畫檔、美工圖案、卡通及圖標
gemology, agate is a common, naturally occurring semiprecious gemstone that is a type of microcrystalline quartz (chalcedony), vintage illustration - 寶石學 幅插畫檔、美工圖案、卡通及圖標岩石