diff --git a/lib/Makefile.am b/lib/Makefile.am
index 9888787772..ea2d1f4577 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -708,6 +708,7 @@ dist_imagesmath_DATA = \
 	images/math/lfloor.png \
 	images/math/lfloor_rfloor.png \
 	images/math/ll.png \
+	images/math/llbracket.png \
 	images/math/llcorner.png \
 	images/math/Lleftarrow.png \
 	images/math/lll.png \
@@ -862,6 +863,7 @@ dist_imagesmath_DATA = \
 	images/math/risingdotseq.png \
 	images/math/root.png \
 	images/math/rparen.png \
+	images/math/rrbracket.png \
 	images/math/Rrightarrow.png \
 	images/math/Rsh.png \
 	images/math/rtimes.png \
diff --git a/lib/images/math/llbracket.png b/lib/images/math/llbracket.png
new file mode 100644
index 0000000000..3e4d957fce
Binary files /dev/null and b/lib/images/math/llbracket.png differ
diff --git a/lib/images/math/rrbracket.png b/lib/images/math/rrbracket.png
new file mode 100644
index 0000000000..2082f6955c
Binary files /dev/null and b/lib/images/math/rrbracket.png differ
diff --git a/src/frontends/qt4/GuiDelimiter.cpp b/src/frontends/qt4/GuiDelimiter.cpp
index 2736c2090c..8303fa6414 100644
--- a/src/frontends/qt4/GuiDelimiter.cpp
+++ b/src/frontends/qt4/GuiDelimiter.cpp
@@ -41,6 +41,7 @@ namespace {
 static char const *  latex_delimiters[] = {
 	"(", ")", "{", "}", "[", "]",
 	"lceil", "rceil", "lfloor", "rfloor", "langle", "rangle",
+	"llbracket", "rrbracket",
 	"uparrow", "updownarrow", "Uparrow", "Updownarrow", "downarrow", "Downarrow",
 	"|", "Vert", "/", "backslash", ""
 };
@@ -114,6 +115,8 @@ void initMathSymbols()
 	math_symbols_["rfloor"] = MathSymbol(0x230B, 99, CMSY_FAMILY);
 	math_symbols_["langle"] = MathSymbol(0x2329, 104, CMSY_FAMILY);
 	math_symbols_["rangle"] = MathSymbol(0x232A, 105, CMSY_FAMILY);
+	math_symbols_["llbracket"] = MathSymbol(0x27e6, 74, STMARY_FAMILY);
+	math_symbols_["rrbracket"] = MathSymbol(0x27e7, 75, STMARY_FAMILY);
 	math_symbols_["uparrow"] = MathSymbol(0x2191, 34, CMSY_FAMILY);
 	math_symbols_["Uparrow"] = MathSymbol(0x21D1, 42, CMSY_FAMILY);
 	math_symbols_["updownarrow"] = MathSymbol(0x2195, 108, CMSY_FAMILY);
@@ -233,6 +236,8 @@ char_type GuiDelimiter::doMatch(char_type const symbol)
 	else if (str == "lfloor") match = "rfloor";
 	else if (str == "rangle") match = "langle";
 	else if (str == "langle") match = "rangle";
+	else if (str == "llbracket") match = "rrbracket";
+	else if (str == "rrbracket") match = "llbracket";
 	else if (str == "backslash") match = "/";
 	else if (str == "/") match = "backslash";
 	else return symbol;
diff --git a/src/mathed/InsetMathDelim.cpp b/src/mathed/InsetMathDelim.cpp
index 0d2fd97607..0653e88b8c 100644
--- a/src/mathed/InsetMathDelim.cpp
+++ b/src/mathed/InsetMathDelim.cpp
@@ -14,10 +14,13 @@
 #include "InsetMathDelim.h"
 
 #include "MathData.h"
+#include "MathFactory.h"
 #include "MathStream.h"
 #include "MathSupport.h"
 #include "MetricsInfo.h"
 
+#include "LaTeXFeatures.h"
+
 #include "support/docstring.h"
 
 #include "frontends/FontMetrics.h"
@@ -58,6 +61,30 @@ Inset * InsetMathDelim::clone() const
 }
 
 
+void InsetMathDelim::validate(LaTeXFeatures & features) const
+{
+	InsetMathNest::validate(features);
+	// The delimiters may be used without \left or \right as well.
+	// Therefore they are listed in lib/symbols, and if they have
+	// requirements, we need to add them here.
+	MathWordList const & words = mathedWordList();
+	MathWordList::const_iterator it = words.find(left_);
+	if (it != words.end())
+	{
+		docstring const req = it->second.requires;
+		if (!req.empty())
+			features.require(to_ascii(req));
+	}
+	it = words.find(right_);
+	if (it != words.end())
+	{
+		docstring const req = it->second.requires;
+		if (!req.empty())
+			features.require(to_ascii(req));
+	}
+}
+
+
 void InsetMathDelim::write(WriteStream & os) const
 {
 	MathEnsurer ensurer(os);
diff --git a/src/mathed/InsetMathDelim.h b/src/mathed/InsetMathDelim.h
index cbea8ec01c..72e204ed11 100644
--- a/src/mathed/InsetMathDelim.h
+++ b/src/mathed/InsetMathDelim.h
@@ -45,6 +45,8 @@ public:
 	///
 	void draw(PainterInfo &, int x, int y) const;
 
+	///
+	void validate(LaTeXFeatures & features) const;
 	///
 	void write(WriteStream & os) const;
 	/// write normalized content
diff --git a/src/mathed/MathSupport.cpp b/src/mathed/MathSupport.cpp
index 95d27b4483..0a87fd69ba 100644
--- a/src/mathed/MathSupport.cpp
+++ b/src/mathed/MathSupport.cpp
@@ -160,6 +160,15 @@ double const brack[] = {
 };
 
 
+double const dbrack[] = {
+	2, 4,
+	0.95, 0.05,  0.05, 0.05,  0.05, 0.95,  0.95, 0.95,
+	2, 2,
+	0.50, 0.05,  0.50, 0.95,
+	0
+};
+
+
 double const corner[] = {
 	2, 3,
 	0.95, 0.05,  0.05, 0.05,  0.05, 0.95,
@@ -299,6 +308,8 @@ named_deco_struct deco_table[] = {
 	{"rbrace",         brace,      2 },
 	{"[",              brack,      0 },
 	{"]",              brack,      2 },
+	{"llbracket",      dbrack,     0 },
+	{"rrbracket",      dbrack,     2 },
 	{"|",              vert,       0 },
 	{"/",              slash,      0 },
 	{"slash",          slash,      0 },