Gemstone Database - Excellence in Gems

No	Gem Variety	Transparency	Colour	Streak	Polariscope Result	General Identification	Mineral Classification	Sillicate Group	Silicate Structural Category	Chemical Formula	Chemical Composition	Refractive Index	DR (Birefringence)	S.G.	Hardness	H-Category	Crystal System	Crystal Class	Crystal Habit	Crystal Form	Axis of Symmetry	Center of Symmetry	Luster	Cleavage	Fracture	Luminescence	Magnetic Properties	Radioactivity	Optical Character	Optical Sign	Pleochroism	Fluorescence	Spectrum (nm)	Special Optical Effects	Typical Inclusions	Occurrence (Countries / Regions including Sri Lanka)
1	Axinite	Transparent–Translucent	BrR,YBr,G	White	Anisotropic	Wedge-shaped brown-violet mineral	Borate	Borate	Non-silicate mineral	(Ca,Fe,Mn)3Al2BO3Si4O12OH	Calcium iron manganese aluminium borosilicate	1.678–1.688	0.010–0.014	3.27–3.29	6.5–7	Medium	Triclinic	Triclinic	Wedge-shaped	Wedge	1	Yes	Vitreous	Distinct	Conchoidal to uneven	Variable	Weak	—	Biaxial	Biaxial (-)	Strong	Variable	—	—	Crystals, feathers	France, Pakistan, Russia, USA, Sri Lanka
2	Kornerupine	Transparent–Translucent	Cl,YG,G,B,Br	White	Anisotropic	Strongly pleochroic green-brown gem	Borate	Borate	Non-silicate mineral	(Mg,Fe)4Al6(Si,Al,B)5O21(OH)	Magnesium aluminium borosilicate	1.665–1.680	0.013	3.2–3.4	6.5–7	Medium	Orthorhombic	Orthorhombic	Prismatic	Prismatic	3	Yes	Vitreous	Distinct	Uneven	Variable	Weak in Fe-rich	—	Biaxial	Biaxial (+/-)	Strong	Variable	—	Cat's-eye rare	Needles, crystals	Sri Lanka, Madagascar, Tanzania, Myanmar, Kenya
3	Sinhalite	Transparent	Ybr,GBr,B,Bl	White	Anisotropic	Brown-yellow Sri Lankan gem	Borate	Borate	Non-silicate mineral	MgAlBO4	Magnesium aluminium borate	1.668–1.707	0.036–0.042	3.45–3.50	6.5–7	Medium	Orthorhombic	Orthorhombic	Granular / wedge-like	Prismatic	3	Yes	Vitreous	Poor	Conchoidal	Variable	—	—	Biaxial	Biaxial (+)	Weak	Variable	—	Cat's-eye rare	Crystals, feathers	Sri Lanka, Myanmar, Madagascar
4	Azurite	Translucent	B	Blue	Anisotropic	Deep blue copper mineral	Carbonate	Carbonate	Non-silicate mineral	Cu3(CO3)2(OH)2	Copper carbonate hydroxide	1.730–1.838	0.050–0.080	3.8	3.5–4	Soft	Monoclinic	Monoclinic	Prismatic / massive	Prismatic	1	Yes	Vitreous	Good	Conchoidal to uneven	Usually inert	—	—	Biaxial	Biaxial (+)	Weak	Variable	436	—	Fibrous inclusions	Morocco, Namibia, USA, Australia, Mexico; Sri Lanka (minor)
5	Malachite	Opaque	G	Green	Anisotropic	Green banded copper mineral	Carbonate	Carbonate	Non-silicate mineral	Cu2CO3(OH)2	Copper carbonate hydroxide	1.655–1.910	0.250–0.255	3.9–4.0	3.5–4	Soft	Monoclinic	Monoclinic	Botryoidal / fibrous / massive	Massive	1	Yes	Silky	Perfect in one direction	Splintery / uneven	Usually inert	—	—	Biaxial	Biaxial (-)	Weak	Variable	437	—	Fibrous banding	DR Congo, Zambia, Russia, Namibia, Australia; Sri Lanka (minor)
6	Fluorite	Transparent	V, G, B, Y, Cl, P	White	Isotropic	Soft mineral with perfect cleavage	Halide	Halide	Non-silicate mineral	CaF2	Calcium fluoride	1.434	—	3.18	4	Soft	Cubic	Isometric	Cubic / octahedral	Cube	4	Yes	Vitreous	Perfect octahedral	Subconchoidal	Common	—	—	Isotropic	—	—	Often strong	—	Fluorescence, color zoning	Color zoning, fluid inclusions	China, Mexico, UK, Spain, South Africa; Sri Lanka
7	Copper	Opaque	Br	Copper	Isotropic	Copper-red malleable metal	Native Element	Native Element	Non-silicate mineral	Cu	Copper	Opaque	Not measurable	8.9	2.5–3	Soft	Cubic	Isometric	Massive / wire / dendritic	Irregular	4	Yes	Metallic	—	Hackly	—	—	—	Isotropic	—	—	—	—	—	Native copper masses	USA, Chile, Russia, DR Congo; Sri Lanka
8	Diamond	Transparent	Cl, Y, Br, B, G, P, Bl	White	Isotropic	Extreme hardness and adamantine luster	Native Element	Native Element	Non-silicate mineral	C	Carbon	2.417	—	3.52	10	10	Cubic	Isometric	Octahedral / cubic	Octahedron	4	Yes	Adamantine	Perfect octahedral	Conchoidal to uneven	Often luminescent	—	—	Isotropic	—	—	Variable, often blue	—	—	Pinpoints, crystals, feathers	Botswana, Russia, Canada, South Africa, Angola, Australia, India; Sri Lanka (alluvial minor)
9	Gold	Opaque	Y	Yellow	Isotropic	Very heavy yellow metal	Native Element	Native Element	Non-silicate mineral	Au	Gold	Opaque	Not measurable	19.3	2.5–3	Soft	Cubic	Isometric	Massive / nugget / dendritic	Irregular	4	Yes	Metallic	—	Hackly	—	—	—	Isotropic	—	—	—	—	—	Native metallic grains	Worldwide including Sri Lanka
10	Amber	Transparent–Translucent	O,Y,B	White	Isotropic	Very light warm resin	Organic	Organic	Organic material	Organic resin	Fossilized organic resin	1.540	—	1.05–1.10	2–2.5	Soft	Amorphous	Amorphous	Massive / nodular	Amorphous	—	No	Resinous	—	Conchoidal	Often fluorescent	—	—	Isotropic	—	—	Blue/green in some UV	—	Electrostatic effect	Insects, bubbles	Baltic region, Dominican Republic, Myanmar, Mexico; Sri Lanka (not major)
11	Alexandrite	Transparent	Green to Red	White	Anisotropic	Green daylight / red incandescent	Oxide	Oxide	Non-silicate mineral	BeAl2O4	Chromium-bearing chrysoberyl	1.746–1.755	0.007–0.011	3.7	8.5	Hard–very hard	Orthorhombic	Orthorhombic	Short prismatic	Prismatic	3	Yes	Vitreous	Poor	Conchoidal to uneven	Variable	—	—	Biaxial	Biaxial (+)	Weak	Variable	444, 470, 680	Color change, cat's-eye	Rutile needles, crystals	Russia, Brazil, Sri Lanka, India, Tanzania
12	Chrysoberyl	Transparent	Y, G, Br	White	Anisotropic	Very hard gem; cat's-eye possible	Oxide	Oxide	Non-silicate mineral	BeAl2O4	Beryllium aluminium oxide	1.746–1.755	0.008–0.010	3.7	8.5	Hard–very hard	Orthorhombic	Orthorhombic	Short prismatic / tabular	Prismatic	3	Yes	Vitreous	Poor	Conchoidal to uneven	Variable	—	—	Biaxial	Biaxial (+)	Weak	Usually none	444, 470	Cat's-eye	Parallel tubes, crystals	Sri Lanka, Brazil, India, Madagascar, Tanzania
13	Hematite	Opaque	Bl,Gr,Br	Red-brown	Aggregate/opaque	Red streak diagnostic	Oxide	Oxide	Non-silicate mineral	Fe2O3	Iron oxide	Opaque	Not measurable	5.2–5.3	5–6	Medium	Trigonal	Trigonal	Massive / tabular	Tabular	3	No	Metallic to earthy	—	Uneven	—	Weak to none	—	Opaque	—	—	—	—	Specular effect	Platelets	Brazil, Australia, South Africa, India, Sri Lanka
14	Ruby	Transparent	Red	White	Anisotropic	Red corundum	Oxide	Oxide	Non-silicate mineral	Al2O3	Chromium-bearing corundum	1.762–1.770	0.008	4.0	9	Hard–very hard	Trigonal	Trigonal	Barrel / prismatic	Trigonal prism	3	No	Adamantine	None / parting	Conchoidal to uneven	Variable	—	—	Uniaxial	Uniaxial (-)	Strong red	Variable	693, 694	Asterism	Rutile silk	Myanmar, Sri Lanka, Mozambique, Thailand, Madagascar, Tanzania
15	Sapphire	Transparent	All	White	Anisotropic	Blue corundum	Oxide	Oxide	Non-silicate mineral	Al2O3	Blue corundum and other fancy-color corundum	1.762–1.770	0.008–0.010	4.0	9	Hard–very hard	Trigonal	Trigonal	Barrel / prismatic	Trigonal prism	3	No	Adamantine	None / parting	Conchoidal to uneven	Variable	—	—	Uniaxial	Uniaxial (-)	Distinct in some colors	Variable	—	Asterism, color change in some	Rutile needles	Sri Lanka, Kashmir (India), Madagascar, Australia, Thailand, Montana USA
16	Spinel	Transparent	All	White	Isotropic	Single RI/isotropic hard gem	Oxide	Oxide	Non-silicate mineral	MgAl2O4	Magnesium aluminium oxide	1.718–1.740	—	3.6	8	Hard–very hard	Cubic	Isometric	Octahedral / granular	Octahedral	4	Yes	Vitreous	—	Conchoidal to uneven	Variable	—	—	Isotropic	—	—	Variable	675, 685 (red spinel)	Star effect rare	Octahedral crystals, fingerprints	Sri Lanka, Myanmar, Tanzania, Vietnam, Tajikistan
17	Taaffeite	Transparent	P,V	White	Anisotropic	Very rare mauve gem	Oxide	Oxide	Non-silicate mineral	BeMgAl4O8	Beryllium magnesium aluminium oxide	1.718–1.722	0.004	3.60–3.62	8–8.5	Soft	Hexagonal	Hexagonal	Rounded / tabular	Tabular	6	No	Vitreous	Indistinct	Conchoidal	Variable	—	—	Uniaxial–anomalous / biaxial-like	Usually uniaxial (+)	Weak	Variable	—	—	Liquid feathers	Sri Lanka, Tanzania, China
18	Apatite	Transparent	G, B, Y, V, P, Br, Cl	White	Anisotropic	Usually green, softer than it looks	Phosphate	Phosphate	Non-silicate mineral	Ca5(PO4)3(F,Cl,OH)	Calcium phosphate with F/Cl/OH	1.632–1.646	0.002–0.004	3.2	5	Medium	Hexagonal	Hexagonal	Prismatic	Hexagonal prism	6	Yes	Vitreous	Poor to indistinct	Conchoidal to uneven	Variable	—	—	Uniaxial	Uniaxial (-)	Weak	Variable	—	Cat's-eye rare	Needle inclusions	Brazil, Mexico, Madagascar, Sri Lanka, Myanmar
19	Turquoise	Opaque	B, G, BG	White	Aggregate	Blue-green opaque waxy stone	Phosphate	Phosphate	Non-silicate mineral	CuAl6(PO4)4(OH)8·4H2O	Hydrated copper aluminium phosphate	1.610–1.650	—	2.6–2.9	5–6	Medium	Triclinic	Triclinic	Massive / nodular	Massive	1	Yes	Waxy	Poor	Subconchoidal / uneven	Usually inert	—	—	Aggregate	Aggregate / N/A	—	Weak to variable	432	—	Host-rock matrix, veins	Iran, USA, China, Egypt, Tibet; Sri Lanka (not major)
20	Aquamarine	Transparent	B	White	Anisotropic	Pale blue beryl	Silicate	Cyclosilicate	Ring silicate	Be3Al2Si6O18	Blue beryl	1.570–1.586	0.006–0.007	2.68–2.74	7.5–8	Hard–very hard	Hexagonal	Hexagonal	Hexagonal prismatic	Hexagonal prism	6	Yes	Vitreous	Indistinct	Conchoidal	Usually weak	—	—	Uniaxial	Uniaxial (-)	Weak blue	Variable	—	Cat's-eye rare	Liquid inclusions, tubes	Brazil, Pakistan, Madagascar, Nigeria, Sri Lanka
21	Benitoite	Transparent	B,V,Cl	White	Anisotropic	Bright blue high-dispersion gem	Silicate	Cyclosilicate	Ring silicate	BaTiSi3O9	Barium titanium silicate	1.757–1.804	0.047	3.65	6–6.5	Medium	Hexagonal	Hexagonal	Tabular / triangular	Trigonal dipyramid	6	No	Vitreous	Poor	Conchoidal	Strong blue UV	—	—	Uniaxial	Uniaxial (+)	Weak	Strong blue	—	Fluorescence	Needles, feathers	California (USA); Sri Lanka (not major)
22	Beryl	Transparent	G, B, Y, P, Cl	White	Anisotropic	Hexagonal crystals; beryl family	Silicate	Cyclosilicate	Ring silicate	Be3Al2Si6O18	Beryllium aluminium silicate	1.580–1.600	0.008–0.009	2.7	7.5–8	Hard–very hard	Hexagonal	Hexagonal	Hexagonal prismatic	Hexagonal prism	6	Yes	Vitreous	Indistinct	Conchoidal to uneven	Usually weak	—	—	Uniaxial	Uniaxial (-)	Weak to distinct	Variable	683, 637 (emerald type)	Cat's-eye rare	Two-phase inclusions, hollow tubes	Brazil, Colombia, Zambia, Afghanistan, Pakistan, Madagascar; Sri Lanka
23	Cordierite	Transparent	B, V, Gr, Y, Cl	White	Anisotropic	Strong dichroism/iolite-like	Silicate	Cyclosilicate	Ring silicate	(Mg,Fe)2Al4Si5O18	Magnesium iron aluminium silicate	1.522–1.578	0.008–0.012	2.6	7–7.5	Hard–very hard	Orthorhombic	Orthorhombic	Short prismatic / granular	Prismatic	3	Yes	Vitreous	Poor	Uneven	Usually inert	—	—	Biaxial	Biaxial (-)	Strong blue-violet/yellow	Usually none	—	Pleochroism	Needles, crystals	Sri Lanka, India, Madagascar, Tanzania, Myanmar
24	Emerald	Transparent	Green	White	Anisotropic	Rich green beryl	Silicate	Cyclosilicate	Ring silicate	Be3Al2Si6O18	Chromium/vanadium-bearing beryl	1.577–1.583	0.006–0.007	2.67–2.78	7.5–8	Hard–very hard	Hexagonal	Hexagonal	Hexagonal prismatic	Hexagonal prism	6	Yes	Vitreous	Indistinct	Conchoidal	Variable	—	—	Uniaxial	Uniaxial (-)	Distinct	Variable red	637, 683	Cat's-eye rare	Three-phase inclusions	Colombia, Brazil, Zambia, Afghanistan, Pakistan, Ethiopia; Sri Lanka
25	Iolite	Transparent	Cl,B,Br,V	White	Anisotropic	Blue stone with obvious dichroism	Silicate	Cyclosilicate	Ring silicate	(Mg,Fe)2Al4Si5O18	Gem cordierite	1.532–1.542	0.008–0.012	2.58–2.66	7–7.5	Hard–very hard	Orthorhombic	Orthorhombic	Short prismatic	Prismatic	3	Yes	Vitreous	Poor	Uneven	Usually inert	—	—	Biaxial	Biaxial (-)	Strong	Usually none	—	Pleochroism	Needles, crystals	Sri Lanka, India, Madagascar, Tanzania, Myanmar
26	Morganite	Transparent	P,Orangish Pink	White	Anisotropic	Pink variety of beryl	Silicate	Cyclosilicate	Ring silicate	Be3Al2Si6O18	Pink beryl	1.577–1.583	0.006–0.008	2.71–2.90	7.5–8	Hard–very hard	Hexagonal	Hexagonal	Hexagonal prismatic	Hexagonal prism	6	Yes	Vitreous	Indistinct	Conchoidal	Variable	—	—	Uniaxial	Uniaxial (-)	Weak pink	Variable	—	Cat's-eye rare	Liquid inclusions, tubes	Brazil, Madagascar, Afghanistan, Mozambique, Nigeria
27	Sugilite	Opaque–Translucent	V,P,Cl,Bl,Gr,Br	White	Aggregate/anisotropic	Strong purple ornamental gem	Silicate	Cyclosilicate	Ring silicate	KNa2(Fe,Mn,Al)2Li3Si12O30	Complex lithium potassium sodium silicate	1.607–1.647	0.040	2.74–2.80	5.5–6.5	Medium	Hexagonal	Hexagonal	Massive	Massive	6	Yes	Vitreous	Poor	Conchoidal to uneven	Variable	—	—	Uniaxial	Uniaxial (-)	Weak	Variable	—	—	Manganese/iron mottling	South Africa, Japan, India, Canada; Sri Lanka
28	Tourmaline	Transparent	Bl, G, P, Vr, B, Y, Cl	White	Anisotropic	Striated crystals; strong pleochroism	Silicate	Cyclosilicate	Ring silicate	Complex borosilicate	Complex boron aluminium silicate	1.621–1.642	0.014–0.022	3.0–3.2	7–7.5	Hard–very hard	Trigonal	Trigonal	Long striated prisms	Trigonal prism	3	No	Vitreous	Poor	Uneven to conchoidal	Variable	Weak to variable	—	Uniaxial	Uniaxial (-)	Strong	Variable	458, 498	Cat's-eye	Growth tubes, liquid inclusions	Sri Lanka, Brazil, Afghanistan, Nigeria, Mozambique, Madagascar
29	Actinolite	Translucent	Gr,B,G,Br,W	White	Anisotropic	Green fibrous amphibole	Silicate	Inosilicate	Chain silicate	Ca2(Mg,Fe)5Si8O22(OH)2	Calcium magnesium iron amphibole	1.600–1.720	0.020–0.030	3.0–3.2	5–6	Medium	Monoclinic	Monoclinic	Fibrous / bladed	Prismatic	1	Yes	Vitreous to silky	Two directions	Splintery	Usually inert	Weak if Fe-rich	—	Biaxial	Biaxial (-)	Weak	Usually none	—	Cat's-eye (fibrous)	Fibres, needles	Canada, Pakistan, Italy, Switzerland, Sri Lanka
30	Diopside	Transparent	G, Bl, Cl	White	Anisotropic	Green pyroxene with cleavage	Silicate	Inosilicate	Chain silicate	CaMgSi2O6	Calcium magnesium silicate	1.675–1.701	0.024–0.030	3.2	5.5–6	Medium	Monoclinic	Monoclinic	Prismatic	Prismatic	1	Yes	Vitreous	Two directions distinct	Uneven	Variable	—	—	Biaxial	Biaxial (+)	Weak to moderate	Variable	505	Cat's-eye rare	Crystals, needles	Sri Lanka, Madagascar, Italy, Pakistan, Russia
31	Enstatite	Transparent–Translucent	YG,B,G,Cl	White	Anisotropic	Orthopyroxene; bronzy sheen possible	Silicate	Inosilicate	Chain silicate	MgSiO3	Magnesium silicate	1.658–1.673	0.010	3.2–3.3	5–6	Medium	Orthorhombic	Orthorhombic	Prismatic	Prismatic	3	Yes	Vitreous	Two directions good	Uneven	Usually inert	—	—	Biaxial	Biaxial (+)	Weak	Usually none	—	Schiller effect in bronzite	Needles, crystals	Sri Lanka, India, Tanzania, USA, Norway
32	Hypersthene	Translucent	Br, GBr	Gray	Anisotropic	Brown bronzy pyroxene	Silicate	Inosilicate	Chain silicate	(Mg,Fe)SiO3	Magnesium iron silicate	1.650–1.700	0.015–0.020	3.4	5–6	Medium	Orthorhombic	Orthorhombic	Prismatic / massive	Prismatic	3	Yes	Vitreous	Two directions good	Uneven	Usually inert	Weak if Fe-rich	—	Biaxial	Biaxial (+/-)	Weak	Usually none	—	Schiller sheen	Crystal inclusions	India, Canada, Norway, Sri Lanka
33	Jadeite	Translucent	G,W,Y,O,Br,V,Bl,Gr	White	Aggregate	Tough jade aggregate	Silicate	Inosilicate	Chain silicate	NaAlSi2O6	Sodium aluminium pyroxene	1.654–1.667	0.012–0.014	3.3–3.5	6.5–7	Medium	Monoclinic	Monoclinic	Granular / fibrous	Massive	1	Yes	Vitreous	Good in two directions	Splintery	Usually inert	—	—	Biaxial	Biaxial (+)	None to weak	Variable	—	—	Granular texture	Myanmar, Guatemala, Japan, Kazakhstan; Sri Lanka (rare)
34	Larimar	Opaque–Translucent	Sky Blue, White	White	Aggregate	Sky-blue pectolite	Silicate	Inosilicate	Chain silicate	NaCa2Si3O8(OH)	Blue pectolite	1.610–1.620	—	2.7–2.9	4.5–5	Soft	Triclinic	Triclinic	Fibrous / massive	Massive	1	Yes	Silky to vitreous	Perfect	Uneven	Variable	—	—	Biaxial	Biaxial (+/-)	—	Variable	—	—	Fibrous structure	Dominican Republic
35	Nephrite	Translucent	G,W,Y,Bl,Br	White	Aggregate	Very tough jade	Silicate	Inosilicate	Chain silicate	Ca2(Mg,Fe)5Si8O22(OH)2	Calcium magnesium iron amphibole aggregate	1.600–1.640	0.020–0.025	2.9–3.1	6–6.5	Medium	Monoclinic	Monoclinic	Fibrous / felted	Massive	1	Yes	Greasy to silky	Two directions in fibers	Splintery	Usually inert	—	—	Biaxial	Biaxial (-)	—	Variable	—	Cat's-eye rare	Fibrous texture	China, New Zealand, Canada, Russia; Sri Lanka (rare)
36	Rhodonite	Translucent	P, Br	White	Anisotropic	Pink stone often with black veins	Silicate	Inosilicate	Chain silicate	MnSiO3	Manganese silicate	1.710–1.735	0.010–0.013	3.6	5.5–6.5	Medium	Triclinic	Triclinic	Massive / tabular	Tabular	1	Yes	Vitreous	Perfect in one direction	Uneven	Variable	—	—	Biaxial	Biaxial (+)	Weak	Variable	545	—	Manganese oxide veins	Australia, Russia, Sweden, Peru; Sri Lanka
37	Spodumene	Transparent	Cl,P,G,B,V	White	Anisotropic	Long prismatic lithium gem	Silicate	Inosilicate	Chain silicate	LiAlSi2O6	Lithium aluminium pyroxene	1.660–1.676	0.015	3.1–3.2	6.5–7	Medium	Monoclinic	Monoclinic	Prismatic	Prismatic	1	Yes	Vitreous	Perfect in two directions	Uneven	Variable	—	—	Biaxial	Biaxial (+)	Strong in kunzite	Variable	—	Color change minor, pleochroism	Tubes, liquid inclusions	Afghanistan, Brazil, Madagascar, USA, Pakistan
38	Almandine	Transparent–Translucent	Red, RV	White	Isotropic	Dark red garnet	Silicate	Nesosilicate	Independent tetrahedra	Fe3Al2(SiO4)3	Iron aluminium garnet	1.760-1.790	—	4.1–4.3	7–7.5	Hard–very hard	Cubic	Isometric	Dodecahedral	Dodecahedron	4	Yes	Vitreous	—	Conchoidal to uneven	Usually inert	Weak in some	—	Isotropic	—	—	Variable	505, 520, 573	Star rare	Crystals, needles	Sri Lanka, India, Madagascar, Brazil, USA
39	Andalusite	Transparent	Br, G, Y, Gr	White	Anisotropic	Brown-green pleochroic gem	Silicate	Nesosilicate	Independent tetrahedra	Al2SiO5	Aluminium silicate	1.634-1.648	0.007-0.013	3.2	7.5	Hard–very hard	Orthorhombic	Orthorhombic	Prismatic	Prismatic	3	Yes	Vitreous	Poor	Uneven	Usually inert	—	—	Biaxial	Biaxial (-)	Strong	Usually none	—	Strong pleochroism	Carbonaceous inclusions	Brazil, Sri Lanka, Spain, Australia, Russia
40	Garnet	Transparent	Vr, O, Y, G, V, Br	White	Isotropic	No cleavage, often rounded crystals	Silicate	Nesosilicate	Independent tetrahedra	X3Y2(SiO4)3	Complex calcium/magnesium/iron/manganese/aluminium silicate	1.730–1.810	—	3.5–4.3	6.5–7.5	Medium	Cubic	Isometric	Dodecahedral / trapezohedral	Dodecahedron	4	Yes	Vitreous	—	Conchoidal to uneven	Usually inert	Variable	—	Isotropic	—	—	Variable	505, 520, 573	Star very rare	Crystals, needles	Sri Lanka, India, Madagascar, Tanzania, Kenya, USA
41	Kyanite	Transparent	B, G, Cl, Gr, Bl	White	Anisotropic	Blue blades; hardness varies by direction	Silicate	Nesosilicate	Independent tetrahedra	Al2SiO5	Aluminium silicate	1.715–1.732	0.015	3.6	4–7	Variable	Triclinic	Triclinic	Bladed	Bladed	1	Yes	Vitreous	Perfect in one direction	Uneven to splintery	Usually inert	—	—	Biaxial	Biaxial (-)	Moderate	Usually none	—	Cat's-eye rare	Needles, cleavage planes	Nepal, India, Brazil, Kenya, Sri Lanka
42	Olivine (Peridot)	Transparent	YG, G, BrG	White	Anisotropic	Olive-green transparent gem	Silicate	Nesosilicate	Independent tetrahedra	(Mg,Fe)2SiO4	Magnesium iron silicate	1.654–1.690	0.036	3.3–4.4	6.5–7	Medium	Orthorhombic	Orthorhombic	Granular / short prismatic	Prismatic	3	Yes	Vitreous	Poor	Conchoidal	Usually inert	Weak to none	—	Biaxial	Biaxial (+)	Weak yellow-green	None to weak	473, 493	—	Lily-pad fractures, crystals	Pakistan, Myanmar, China, USA, Egypt; Sri Lanka (minor)
43	Phenakite	Transparent	Cl,Y,P,B	White	Anisotropic	Colorless high-hardness gem	Silicate	Nesosilicate	Independent tetrahedra	Be2SiO4	Beryllium silicate	1.654–1.670	0.016	2.96–3.00	7.5–8	Hard–very hard	Trigonal	Trigonal	Rhombohedral	Rhombohedron	3	No	Vitreous	Indistinct	Conchoidal	Variable	—	—	Uniaxial	Uniaxial (+)	—	Variable	—	—	Liquid inclusions	Brazil, Russia, Madagascar, Myanmar, Sri Lanka
44	Sillimanite	Translucent	Cl, Y, G, Br	White	Anisotropic	Fibrous/prismatic brown mineral	Silicate	Nesosilicate	Independent tetrahedra	Al2SiO5	Aluminium silicate	1.659–1.680	0.014–0.021	3.2	6.5–7.5	Medium	Orthorhombic	Orthorhombic	Fibrous / prismatic	Prismatic	3	Yes	Vitreous	Poor	Splintery to uneven	Usually inert	—	—	Biaxial	Biaxial (+)	Weak	Usually none	—	Cat's-eye (fibrous)	Fibrous inclusions	Sri Lanka, India, Myanmar, USA
45	Sphene (Titanite)	Transparent	Y,B,G	White	Anisotropic	Fire and wedge shape	Silicate	Nesosilicate	Independent tetrahedra	CaTiSiO5	Calcium titanium silicate	1.900–2.034	0.100–0.135	3.4–3.6	5–5.5	Soft	Monoclinic	Monoclinic	Wedge-shaped	Wedge	1	Yes	Adamantine	Distinct	Conchoidal to uneven	Variable	—	—	Biaxial	Biaxial (+)	Strong	Variable	—	Very high dispersion	Needles, crystals	Sri Lanka, Pakistan, Madagascar, Brazil, Russia
46	Topaz	Transparent	Cl, B, Y, Br, P, O	White	Anisotropic	Hard gem with perfect cleavage	Silicate	Nesosilicate	Independent tetrahedra	Al2SiO4(F,OH)2	Aluminium fluorosilicate hydroxide	1.610–1.628	0.008–0.010	3.4–3.6	8	Hard–very hard	Orthorhombic	Orthorhombic	Prismatic	Prismatic	3	Yes	Vitreous	Perfect basal	Subconchoidal to uneven	Variable	—	—	Biaxial	Biaxial (+)	Usually weak	Variable	—	Cat's-eye rare	Two-phase inclusions, feathers	Brazil, Pakistan, Russia, Nigeria, Sri Lanka, Afghanistan
47	Zircon	Transparent	Cl, B, Y, Br, G	White	Anisotropic	Very high RI and fire	Silicate	Nesosilicate	Independent tetrahedra	ZrSiO4	Zirconium silicate	1.810–1.984	0.002-0.059	4.6–4.7	7.5	Hard–very hard	Tetragonal	Tetragonal	Prismatic / dipyramidal	Tetragonal prism	4	Yes	Adamantine	Indistinct	Conchoidal to uneven	Variable	—	Weak in some stones	Uniaxial	Uniaxial (+)	Weak	Variable	—	—	Halos, crystals	Sri Lanka, Cambodia, Myanmar, Australia, Tanzania
48	Danburite	Transparent	Cl,Y,Br,P	White	Anisotropic	Colorless transparent gem	Silicate	Sorosilicate	Double tetrahedra	CaB2(SiO4)2	Calcium borosilicate	1.630–1.636	0.006	3.0	7–7.5	Hard–very hard	Orthorhombic	Orthorhombic	Prismatic	Prismatic	3	Yes	Vitreous	Distinct	Uneven to conchoidal	Variable	—	—	Biaxial	Biaxial (+)	Weak	Variable	—	Cat's-eye rare	Liquid inclusions, feathers	Mexico, Myanmar, Japan, Madagascar, Sri Lanka
49	Epidote	Transparent–Translucent	YG, BrG	Gray	Anisotropic	Pistachio-green crystals	Silicate	Sorosilicate	Double tetrahedra	Ca2(Al,Fe)3(SiO4)3(OH)	Calcium aluminium iron sorosilicate hydroxide	1.736–1.770	0.034	3.3–3.5	6–7	Medium	Monoclinic	Monoclinic	Prismatic	Prismatic	1	Yes	Vitreous	Perfect in one direction	Uneven	Usually inert	Weak if Fe-rich	—	Biaxial	Biaxial (-)	Strong green-yellow	Usually none	530, 560	—	Needles, crystals	Austria, Pakistan, Norway, USA; Sri Lanka (rare)
50	Tanzanite	Transparent	V,B,G,Br	White	Anisotropic	Blue-violet zoisite	Silicate	Sorosilicate	Double tetrahedra	Ca2Al3(SiO4)3(OH)	Blue-violet zoisite	1.692–1.700	0.008	3.35	6–7	Medium	Orthorhombic	Orthorhombic	Prismatic	Prismatic	3	Yes	Vitreous	Perfect in one direction	Uneven	Variable	—	—	Biaxial	Biaxial (+)	Strong trichroism	Variable	—	Pleochroism	Fluid inclusions	Tanzania; Sri Lanka (marketed, not source)
51	Agate	Translucent	Br,Gr,B	White	Aggregate	Banded chalcedony	Silicate	Tectosilicate	Framework silicate	SiO2	Silica	1.530–1.540	—	2.6	6.5–7	Medium	Cryptocrystalline aggregate	Cryptocrystalline	Banded massive	Compact	—	No	Waxy	—	Conchoidal	Usually inert	—	—	Aggregate	Aggregate / N/A	—	Variable	—	Banding	Banding, fluid inclusions	Brazil, India, Uruguay, Madagascar, Sri Lanka
52	Chert	Opaque	W, Gr, Br, Bl, Y	White	Aggregate	Gray opaque silica	Silicate	Tectosilicate	Framework silicate	SiO2	Silica	1.535–1.540	—	2.6	7	Hard–very hard	Cryptocrystalline aggregate	Cryptocrystalline	Massive	Compact	—	No	Dull	—	Conchoidal	Usually inert	—	—	Aggregate	Aggregate / N/A	—	Usually none	—	—	Microcrystalline quartz grains	Worldwide including Sri Lanka
53	Ekanite	Transparent–Translucent	Brownish Green	White	Anisotropic	Rare radioactive gem mineral	Silicate	Tectosilicate	Framework silicate	Ca2ThSi8O20	Calcium thorium silicate	1.597	—	3.28–3.32	5.5–6.5	Medium	Tetragonal	Tetragonal	Massive / prismatic	Prismatic	4	Yes	Greasy to vitreous	Indistinct	Conchoidal	Variable	—	Radioactive	Uniaxial	Uniaxial (+)	Weak	Variable	—	—	Metamict zones	Sri Lanka (type locality), Tanzania, Madagascar
54	Feldspar	Translucent	W, Gr, P, G, B, Br, Cl	White	Anisotropic	Good cleavage, common rock-former	Silicate	Tectosilicate	Framework silicate	KAlSi3O8 etc.	Potassium/sodium/calcium aluminium silicate	1.518–1.526	0.008	2.55–2.76	6	Medium	Monoclinic/Triclinic	Monoclinic / Triclinic	Tabular / blocky	Tabular	2 or 1	Yes	Vitreous	Two directions perfect	Uneven	Variable	—	—	Biaxial	Biaxial (+/-)	Usually weak	Variable	—	Adularescence in moonstone, aventurescence in sunstone	Exsolution lamellae	Sri Lanka, India, Madagascar, USA, Norway
55	Flint	Opaque	Gr, Bl, Br	White	Aggregate	Dark opaque silica	Silicate	Tectosilicate	Framework silicate	SiO2	Silica	1.530–1.540	—	2.6	7	Hard–very hard	Cryptocrystalline aggregate	Cryptocrystalline	Massive	Compact	—	No	Waxy	—	Conchoidal	Usually inert	—	—	Aggregate	Aggregate / N/A	—	Usually none	—	—	Micro quartz grains	Worldwide including Sri Lanka
56	Jasper	Opaque	Br, G, Y	White	Aggregate	Opaque patterned quartz	Silicate	Tectosilicate	Framework silicate	SiO2	Silica	1.530–1.540	—	2.6	6.5–7	Medium	Microcrystalline aggregate	Microcrystalline	Massive	Compact	—	No	Dull	—	Conchoidal to uneven	Usually inert	—	—	Aggregate	Aggregate / N/A	—	Usually none	—	—	Iron oxide particles	Worldwide including Sri Lanka
57	Labradorite	Translucent	Gr, Bl, B, G	White	Anisotropic	Gray stone with blue/green flash	Silicate	Tectosilicate	Framework silicate	(Ca,Na)(Al,Si)4O8	Calcium sodium aluminium silicate	1.560–1.570	0.005–0.006	2.7	6–6.5	Medium	Triclinic	Triclinic	Tabular / blocky	Tabular	1	Yes	Vitreous	Two directions perfect	Uneven	Variable	—	—	Biaxial	Biaxial (+/-)	None to weak	Variable	—	Labradorescence	Lamellae	Canada, Madagascar, Finland, India, Australia; Sri Lanka
58	Lapis Lazuli	Opaque	B	Light blue	Aggregate	Blue rock with pyrite flecks	Silicate	Tectosilicate	Framework silicate	Complex rock (lazurite etc.)	Rock composed chiefly of lazurite with calcite/pyrite	1.500–1.510	—	2.7–2.9	5–5.5	Soft	Aggregate rock	Aggregate	Massive	Massive	—	No	Dull	Poor	Uneven	Variable	—	—	Aggregate	Aggregate / N/A	—	Weak variable	—	—	Pyrite grains, calcite	Afghanistan, Chile, Russia, Pakistan; Sri Lanka (marketed, not major source)
59	Moonstone	Translucent	B,W,O	White	Anisotropic	Soft glow over body color	Silicate	Tectosilicate	Framework silicate	KAlSi3O8	Orthoclase/adularia feldspar	1.518–1.526	0.008	2.55–2.62	6–6.5	Medium	Monoclinic	Monoclinic	Tabular / massive	Tabular	2	Yes	Vitreous	Two directions perfect	Uneven	Variable	—	—	Biaxial	Biaxial (+/-)	Usually weak	Variable	—	Adularescence	Lamellae	Sri Lanka, India, Madagascar, Myanmar, Tanzania
60	Quartz	Transparent	Cl, V, Y, P, Br, Gr, Bl, G, B	White	Anisotropic	Common transparent silica	Silicate	Tectosilicate	Framework silicate	SiO2	Silica	1.544–1.553	0.009	2.65	7	Hard–very hard	Trigonal	Trigonal	Hexagonal prism	Trigonal/hexagonal prism	3	No	Vitreous	—	Conchoidal	Variable	—	—	Uniaxial	Uniaxial (+)	None to weak	Variable	—	Asterism rare, cat's-eye rare	Fluid inclusions, needles	Brazil, Madagascar, USA, India, Sri Lanka, worldwide
61	Rhodesite	Translucent	Cl,W,YW,Y,Gr,G	White	Aggregate/anisotropic	Rare pale zeolitic material	Silicate	Tectosilicate	Framework silicate	—	Rare zeolite-group name often cited inconsistently	1.520–1.540	0.010–0.020	2.2–2.4	4–5	Soft	Monoclinic?	Monoclinic?	Fibrous / massive	Massive	1	Yes	Vitreous	Perfect to good	Uneven	Variable	—	—	Biaxial	Biaxial	Weak	Variable	—	—	Fibrous textures	Reported from limited localities; verify source-specific identity
62	Scapolite	Transparent–Translucent	Cl,P,Y	White	Anisotropic	Prismatic tetragonal gem	Silicate	Tectosilicate	Framework silicate	(Na,Ca)4Al3Si9O24Cl,CO3,SO4	Sodium calcium aluminium silicate with anions	1.544–1.568	0.016	2.57–2.74	5.5–6	Medium	Tetragonal	Tetragonal	Prismatic	Tetragonal prism	4	Yes	Vitreous	Poor	Uneven	Variable	—	Weak in some	Uniaxial	Uniaxial (-/+)	Weak	Variable	—	Cat's-eye rare	Needles, tubes	Sri Lanka, Tanzania, Madagascar, Myanmar, Canada
63	Sodalite	Opaque–Translucent	B	White	Isotropic	Royal-blue ornamental stone	Silicate	Tectosilicate	Framework silicate	Na8(Al6Si6O24)Cl2	Sodium aluminium chloride silicate	1.483	—	2.14–2.40	5.5–6	Medium	Cubic	Isometric	Massive	Massive	4	Yes	Vitreous to greasy	Poor	Uneven	Orange fluorescence common	—	—	Isotropic	—	—	Often orange under UV	—	Hackmanite tenebrescence in some	Veins, white calcite	Canada, Namibia, Brazil, Greenland, Russia; Sri Lanka
64	Sunstone	Transparent–Translucent	O,R,Y,Br,P	White	Anisotropic	Sparkling feldspar	Silicate	Tectosilicate	Framework silicate	(Na,Ca)(Al,Si)4O8	Aventurescent feldspar	1.525–1.547	0.008–0.010	2.62–2.66	6–6.5	Medium	Triclinic/Monoclinic	Triclinic / Monoclinic	Tabular	Tabular	1 or 2	Yes	Vitreous	Two directions perfect	Uneven	Variable	—	—	Biaxial	Biaxial (+/-)	Weak	Variable	—	Aventurescence	Copper platelets / hematite	India, USA (Oregon), Norway, Tanzania, Sri Lanka
65	Pyrite	Opaque	Y	Greenish black	Isotropic	Brassy cubic crystals	Sulfide	Sulfide	Non-silicate mineral	FeS2	Iron sulfide	Opaque	Not measurable	5.0	6–6.5	Medium	Cubic	Isometric	Cubic / pyritohedral	Cube	4	Yes	Metallic	Poor	Uneven to conchoidal	—	Usually none	—	Isotropic	—	—	—	—	—	Framboidal texture, mineral grains	Spain, Peru, Italy, USA, China; Sri Lanka
66	Opal	Translucent	W, Bl, B, G, O, P	White	Isotropic	Hydrated silica with play-of-color possible	—	—	Non-silicate mineraloid	SiO2·nH2O	Hydrated silica	1.440–1.470	—	2.1	5.5–6.5	Medium	Amorphous	Amorphous	Massive / nodular	Amorphous	—	No	Waxy	—	Conchoidal to uneven	Variable	—	—	Isotropic	—	—	Variable	—	Play-of-color	Water inclusions, spheres	Australia, Ethiopia, Mexico, Brazil; Sri Lanka